I'm very thing, about 115 lbs. my stomach feels pretty hard on the inside when I press down. Before it used to feel squishy and now it's a little firm. I heard it's possible for your stomach to harden in early pregnancy. I can't test for another week or 2. So nervous I might be pregnant when I felt I was being safe with the condom and using the pull out method at the same time.
The first thing I want you to do is relax ;) Stressing about anything that much is not good for you, no matter the problem.
Next, if you use condoms as directed, there is a very small risk of you getting pregnant. I understand you being cautious about it, so I would recommend you use two methods of birth control, like condoms and birth control, or condoms with another contraceptive ( spermicide, diaphragm, etc.).
I think birth control pills might be good for you, because it can actually make your periods regular. I have never heard of them making you infertile, and since your blood work came back fine, I wouldn't worry about that right now. Taking the pill for a few months to see if your period becomes more regular shouldn't hurt your chances of getting pregnant later in life. And having two methods of contraception will allow you to stop using the pull out method, which is NOT reliable, and is probably causing more stress than needed during what should be a stress relieving time.
As long as you are using condoms there shouldn't be a risk. The pull out method is ridiculous. Doesn't work and must be a passion killer. Stop obcessing. As for birth control, try iud. Doesn't use any hormones. Or mini pill which uses less hormones.