Sex for 1st time & I started feeling sick & getting cramps 30 mins. After & up to now it's the 3rd day. Didn't fully cum. But pre cum maybe? Preg?

Not from preg. But symptoms are either emotional or aggravation of a preexisting condition like ibs ic or endometriosis. Sex is an emotionally connecting experience despite what r society tries to say -sex outside a committed relationship is stressful and could cause the symptoms ur experiencing as well. It's possible u could become pregnant but it takes a while for these symptoms to develop.