What Causes Swelling Of Abdomen And Delay In Periods?

Hi umm I just had a question well it has a story to it I was on birth control and stop January and had unprotected sex with my partner in February but since then I haven t gotten my period and I been getting weird symptoms like pregnancy symptoms and I took 2 pregnancy test and both negative I went to a obgyn or whatever that doctor is called and took another one and came negative but my abdomen is swollen and I m getting pregnancy symptoms and I m just confused