My doctor took blood test, I took three pregnancy test about two months ago and I took two bleach pregnancy tests yesterday all of them where negative. I had all my periods but there where solid pieces (It looked like my uterus lining ) but my stomach is lightly swollen and I have constant abdominal pain / cramps. My breast are also swollen and hard and was also constipated the last few days. I'm also gassy and my stomach growls a lot .I had a bad stomach virus is February that had me out for longer than a week. I went to see my doctor who was worried about my liver and thyroid gland she took blood test and the results where all negative. She did say that I have irritable bowel syndrome. Everything went back to normal but now the swelling started. I did eat more bread the last few weeks than usual. I stress over nothing and always over react before anything has happen. My mind is playing games and making me think I might be pregnant even if it is clear that I am not. I do stress over little things and quite a lot. But I know I am not pregnant but what can this be?

The doctor gave you one suggestion, and you perhaps did not stay on the diet he recommended. But that is also why he took blood test, and found out, it was not those.
So you go back to doctor and he does additional tests till he discovers the one, or even two or three things that are wrong.

No you are no pregnant, if doctors test, and home test shows not pregnant.

Also, there is a bleach test, a pine sol test, and a few others. I have read where they will show some men pregnant, and not reliable at all. But then some believe.

Really time for additional medical testing

What were the instructions for the irritable bowl syndromes and are you following them? The thing do do would be telling your doctor that your symptoms have returned and see what the next step is.

Your reference to being pregnant leads me to believe that you fear being so, and may be overly worried about it, so I will ask if you are on birth control of any kind?

Happens to me frequently with IBS. Watch your diet and avoid eating foods that make you gassy. There is no real diet for IBS as everyone has different foods that trigger it. You just have to find out what triggers yours.

Just one of many suggestions: no more bread! In fact try eliminating all foods with flour in them for a while to see what happens. You could possibly have candida overgrowth (candida is yeast, and we all have some of it normally, to aid in digestion, but many things can throw it out of whack).
Sugar is what feeds yeast, so eliminating sugar in all of its simple forms like candy, desserts, alcohol and flours.
AND you need tp boost your good gut bacteria with probiotics or yogurt high in good bacteria.

What was your treatment, if any, for the stomach virus?