It's most probable that the cramps you are feeling are menstrual, not from pregnancy, since it would be both rather late in your cycle to have ovulated, and also really early for you to feel any symptoms if you were pregnant. It takes 5 days for the embryo to develop enough to shed its shell, and then between days 6 and maybe 10, it floats around getting bigger and finally implants in the uterine sidewall. Before it implants, the body does not have any signal at all of being pregnant (since the embryo is free floating). Even after it implants, many women report that a test told them they were pregnant long before they felt any symptoms. Cannot guarantee that what you have is your period coming, but it sounds like it.
No he did not ejaculate prior to sex
It is not extremely likely that you got pregnant this way, but it is possible. Do you know if your boyfriend had ejaculated prior to the sex?
I am worried that there may have been pre-*** but neither of us know if there was.