2 DPO Symptoms?

*** I will start off saying that I know that IF this is my cycle that it wouldn't have implanted yet. So I know that these symptoms shouldn't be from being pregnant.

Saturday evening I had the first postive opk. Yesterday night I had cramps and heart burn. This morning I woke up to more cramps, sore nipples which have been getting worse, and headaches. Does anyone else have these types of symptoms after ovulation? I didn't have any symptoms during ovulation.