Pregnancy problem. Hello doctor.

Hello doctor. Thanks for helping me. Well i am married and my last sexual intercourse was in the 15th of december. I feel full and bloated and burp and have gas all the time and i have alittle pain from time to time in my anal. I also have pain in both sides of my lower back and an itchy vag*** with transparent to white losses. I thought i was pregnant in the begginig but i had my periods on time and with the same quantity of blood. Three weeks after the intercourse i had a quantitative hcg blood test and i was taking antibiotics then but it was negative. And today i had an abdominal ultrasound check but nothing showed on the screen and the doc said i had an inflamation in the intestines. What do you think please. I really need to know what it is?