Tapering Download Speeds, Intermittent Connection Loss

Please forgive me in advance, I work for a start up and I am the poor soul who is in charge of the internet for 30 angry people.

We have an ER-8 and 3 UAP-Pros at my office. For months, we have had no issues with the internet, but this week, we have had tapering download speeds and intermittent connection issues. I have updated all of the hardware firmware to the latest version, and I believe my configs are good, but I would really appreciate someone giving my edgerouter config a once-over just to see if anything I have setup could be causing this issue. 

The setup is ultra straight forward, no weird stuff (to my knowledge). Could anything here be causing users' downloads to slow to a halt, then start back up? Or for people to intermittently lose connection, but some not? 

Thank you very much, I really appreciate any advice you can provide.

firewall {
    all-ping enable
    broadcast-ping disable
    ipv6-receive-redirects disable
    ipv6-src-route disable
    ip-src-route disable
    log-martians enable
    name WAN_IN {
        default-action drop
        description "WAN to internal"
        rule 10 {
            action accept
            state {
                established enable
                related enable
            }
        }
        rule 20 {
            action drop
            state {
                invalid enable
            }
        }
    }
    name WAN_LOCAL {
        default-action drop
        description "WAN to router"
        rule 10 {
            action accept
            state {
                established enable
                related enable
            }
        }
        rule 20 {
            action drop
            state {
                invalid enable
            }
        }
    }
    receive-redirects disable
    send-redirects enable
    source-validation disable
    syn-cookies enable
}
interfaces {
    ethernet eth0 {
        address 192.168.1.1/24
        description Local
        duplex auto
        mtu 1500
        speed auto
    }
    ethernet eth1 {
        address dhcp
        description Internet
        dhcp-options {
            default-route update
            default-route-distance 210
            name-server no-update
        }
        duplex auto
        firewall {
            in {
                name WAN_IN
            }
            local {
                name WAN_LOCAL
            }
        }
        mac 72:f1:96:16:55:e2
        mtu 1500
        speed auto
    }
    ethernet eth2 {
        address 192.168.2.1/24
        description "Local 2"
        duplex auto
        speed auto
    }
    ethernet eth3 {
        duplex auto
        speed auto
    }
    ethernet eth4 {
        duplex auto
        speed auto
    }
    ethernet eth5 {
        duplex auto
        speed auto
    }
    ethernet eth6 {
        duplex auto
        speed auto
    }
    ethernet eth7 {
        duplex auto
        speed auto
    }
    loopback lo {
    }
}
service {
    dhcp-server {
        disabled false
        hostfile-update disable
        shared-network-name LAN1 {
            authoritative disable
            subnet 192.168.1.0/24 {
                default-router 192.168.1.1
                dns-server 209.244.0.3
                dns-server 209.244.0.4
                lease 86400
                start 192.168.1.21 {
                    stop 192.168.1.240
                }
            }
        }
        shared-network-name LAN2 {
            authoritative disable
            subnet 192.168.2.0/24 {
                default-router 192.168.2.1
                dns-server 209.244.0.3
                dns-server 209.244.0.4
                lease 86400
                start 192.168.2.21 {
                    stop 192.168.2.240
                }
            }
        }
        use-dnsmasq disable
    }
    dns {
        forwarding {
            cache-size 150
            listen-on eth0
            listen-on eth2
            listen-on eth1
            name-server 209.244.0.3
            name-server 209.244.0.4
        }
    }
    gui {
        http-port 80
        https-port 443
        older-ciphers enable
    }
    nat {
        rule 5010 {
            outbound-interface eth1
            type masquerade
        }
    }
    ssh {
        port 22
        protocol-version v2
    }
}
system {
    conntrack {
        expect-table-size 4096
        hash-size 4096
        table-size 32768
        tcp {
            half-open-connections 512
            loose enable
            max-retrans 3
        }
    }
    host-name ubnt
    login {
        user ubnt {
            authentication {
                encrypted-password --censored--
            }
            level admin
        }
    }
    name-server 127.0.0.1
    ntp {
        server 0.ubnt.pool.ntp.org {
        }
        server 1.ubnt.pool.ntp.org {
        }
        server 2.ubnt.pool.ntp.org {
        }
        server 3.ubnt.pool.ntp.org {
        }
    }
    syslog {
        global {
            facility all {
                level notice
            }
            facility protocols {
                level debug
            }
        }
    }
    time-zone UTC
    traffic-analysis {
        dpi enable
        export enable
    }
}
traffic-control {
    smart-queue 12Twenty {
        download {
            ecn enable
            flows 1024
            fq-quantum 1514
            limit 10240
            rate 120mbit
        }
        upload {
            ecn enable
            flows 1024
            fq-quantum 1514
            limit 10240
            rate 20mbit
        }
        wan-interface eth1
    }
}