Clomid period question

Ok so I know clomid can mess up your periods making them heavier, longer, but what about shorter? I ended my third round and got my "period" yesterday, small amount of red blood but mostly dark brown. Between last night and this AM only small amount of dark brown blood. And period seems to have stopped. Could I still be pregnant? Anyone have this happen to them? I did take a test btw and its negative BUT I also got my "period" early on day 24 so it's not even the 28 day mark.