Heavy lower abdomen.

Hello, i'm a 19 year old female with a regular 28-20 day cycle. My last period was about two weeks ago [May 22] and a week later [May 30] i had sex. There were some moments in which he used a condom and others where he didn't. He never came inside me, he came over me, if that makes sense. Four days after sex [May 13] i started to get a white discharge, so i concluded it to be ovulation, because i get that discharge every month. Now these past couple of days I've had nausea and heartburn, it could be my gastritis [due to extreme drinking two months ago] acting up, or the fact that i recently started a diet and exercise regiment. In this week alone i lost 8 pounds. I took ibuprofen regularly today to see if it would decrease the heaviness. It did for a while, all i had was the regular dull aches on the left side of my lower abdomen from ovulating, but about last night i got a yellow discharge, and my feet were swollen. Could that have been the ibuprofen? Today when i woke up my abdomen still felt heavy, with some cramping, the usual nausea, and this is new: my vagina is kind of itchy. This happened about two months ago too, but without the itchy vagina. I psyched myself out thinking i was pregnant cause i couldn't eat from the nausea and i had sever heartburn. Turns out it was the beginning symptoms of my gastritis and my period came a week late, 38 days after last period. Last month it came 32 days after last period. Could my period be painfully trying to regulate itself again? Why is my abdomen soooo heavy? Could i be pregnant and be showing symptoms 7 days after sex? Someone pleaaase help me! Thanks in advance.