T-mobile 3g speeds after being throttled?

[FranciscoR]

Hey guys so I am a t-mobile customer with the 50 dollar everything unlimited plan although they do throttle my web speeds once i go past 100 mb. For some reason I have already used up 1.3gb and I still get average 3g speeds of 5 mbps. Going into the tmobile app on my phone i can see it says "warning your web speeds have been reduced to 2g" so could this be a system error? I know its very unlikely since the system is automated but what could be causing this?

Thanks in advance!