vaginal discharge. more a iud? std?

Britney
Okay ladies, 
I had chlamidya like three weeks ago and I got on the medication. I didn't have sex for a week so I am clean from that now. But in the past three days I have noticed that I have been getting a white/light yellowish discharge, it's not clumpy its watery and the smell is acidic like a lemon. What the fuck is happen ? Anyone know? I have had sex within the past week like every other day and it's been with him going raw. Can it be an std ? Or could it be his cum just messing with my PH? Or can it be the fact that I got the Mireya IUD in the middle of this past December ? My period is also supposed to start in about 5days if that's of any relevance. Please help me guys X.X