Latency/Recording Problem.. Please help

[Dbrown36UT]

Ok, so I've been using ableton for a minute now mainly for recording massive midi in arrangement view. I dont have a spectacular pc but outside of adjusting the buffer size and what have you, I've never had too harsh of a latency issue. For whatever reason, after messing with some preferences (maybe just ironic timing), my midi recording is just failing on me. The notes play perfectly fine when not recording, but the second I try to actually record it misses notes left and right, especially fast human like playing/soloing. I've never had this problem till recently and it's debilitating for my producing.. It just like loses IQ and barely records anything at all unless it insanely slow. Is this a computer issue and my pc has just had enough? I hope not.. Also, I've always just hit record and it played the song and records instantly together. For some reason now, the record button lights up but wont record till I actually hit play on the song, not sure if they're related. I've tried everything I normally do as far as buffer.. And CPU load is very low, but even the EQ on the track looks laggy.. this is definetely a new problem..Shit guys, help me please! Scaring me