Honestly not sure?

I am on birth control and I do take it like I'm supposed to but have only been on it for 3 weeks almost and my s/o thought that it would be of great interest to start releasing in me (finally) well the first time he did the next morning I had blood streaked mucus and pinkish/darker colored discharge and had that discharge for about a day and a half, the second time he released in me it didn't do anything and yesterday was the 3rd time he had released in me. Having slight small cramps I know its way to early to detect or even tell a symptom if it was the big P word but why am I having these slight small cramps? Anyone else have this?