Pregnant???

So I only just got Mirena, but a little before hand I had sex. It was protected but I worry a lot. As told my period is lasting forever I’m around day 14, but cramps are still here and it seems like My stomach is getting larger I’m also gaining weight. Is it possible I was pregnant before they put it in? Would the doctors know? Or am I just overthinking things? P.S. he did pull out as well even with the condom but he never came we just stopped early because someone came inside the house

Edit: I had never been examined before so they never gave me a test. I didn’t say I was active because I had a very traditional doctor and I’m only 16