Worried about being pregnant, help?

So I don't know if you can get pregnant from precum but I'm pretty worried. I have a question on the dates and if it could be possible I would already begin feeling these symptoms or if it is too soon. Or if it is possible for pregnancy to occur? I think I'm beginning to psych myself out. So I had unprotected sex on these days 12/31, 1/6, & 1/8. We used the pull out method each time. I started my period 1/12-1/18. The reason I'm so worried is because I've been cramping for a week 1/2 now and I'm not supposed to start my period until the 12th or the 10th of February. I feel sick and tired. Idk if my body is trying to prepare for my upcoming period or if this should be something I worry about. I don't want to take a test yet until I'm completely sure. Help me please.