I know you posted some time ago and I assume you have resolved the issue by now. But it is VERY unlikely that you are pregnant. Nature makes it easy, but not THAT easy.
It is true that precum CAN include some sperm, especially as his body "ramps up" to orgasm, or if he is approaching a second ejaculation and he hasn't urinated between them to "clear the system" so to speak. But rubbing your genitals together, even bathing your clitoris in his precum (which feels lovely, by the way) is not likely to get you pregnant. In fact, he could actually ejaculate against your vulva and clitoris, and chances are still low. Cumming on your belly has the same low risk, except that sperm may have been leaking out into you prior to his pulling out. Even cumming inside your anus and then having it drip down toward your vagina would not automatically result in pregnancy. Sperm has to be pushed into you to get it started toward your cervix.
Once inside your vagina there are all kinds of hazards and roadblocks for the sperm to reach their target (which is why he ejaculates so many of them each time he cums), so the miniscule number that might possibly be in his precum would literally have an "uphill" battle to get deep enough inside you to make you pregnant. The interior environment of your vagina is designed to actually make it hard for the sperm to survive very long. This is kind of an elegant method of ensuring that only the strongest, healthiest, and most vigorous sperm get to the target. HOWEVER, if you are all wet from him (and yourself), then do be careful about slipping fingers into your vagina, as you COULD push any sperm present on the OUTSIDE in toward your cervix. Chances are still low, though.
And any number of other factors can give you tender breasts or irregular periods, etc., besides pregnancy. Speak to your gynecologist, as you could be having symptoms of something more serious that needs your attention.