your pain is probably ovulation. i have that and when i was trying to get prenant, i took those tests and i could always notice a little twinge of pain by my ovaries when i was ovulating. i would never tell you any drug is safe while pregnant, but i went by the theory that until the test came back positive, i did all i wanted to do. i was refinishing our hardwood floors, sanding and using polyurithane when i got pregnant. i stopped doing all the things the day the test came back positive. i did not take anything while pregnant and my son was born perfectly fine. you can take some things that will calm your stomach, but if you are going to get pregnant, you need to eat better than cake etc. You need certain vitamins and minerals that are in real foods and as much as i am a junk eater and i would love on junk if i could, you can't when you are pregnant and you can't with a kid if you want him/her to eat right also.
Good luck and have fun with the baby making this weekend. It is the best experience in the world to have a baby grow inside you and be born and raise him/her. I wish i wasn't 41 or I would do it again today.
TRY to live each day like it were your last