What Causes Severe Mood Swings, Gastritis And Increased Appetite?

My last period was 10-3, lasted for 5 days and was normal (no cramping, clotting, heavy).....my husband and I had sex ( with protection, but had an accident) on the 17th, which happened to be my ovulation day.....on 10-27 I had what seems like a regular period except it was not as heavy, not as much clotting (with cramping which I rarely have) lasted only 3 1/2 days and was early. Tired, extremely moody, lots of gas, hungry all the time and a bout of virus like diarrhea and nausea.... I have taken a pt and it came back neg.....if this was decidual bleeding can this affect a hpt, and if so when could I get an accurate result? Have I just tested too early? Im really confused and any advice would be greatly helpful!! Sorry for all the TMI