pregnant again?

I had a molar pregnancy in September. I had my D&C on September 9th. I got on the shot right after the procedure. I bled for a long time. It stopped earlier this month. But now I’m worried. Idk if i had a period since . It was just expulsion of dark blood (light and then heavier on some days). I had sex three days ago. Unprotected and pull out method. Now I know it’s wayyy to early to know if I’m pregnant. But I haven’t gotten the shot again since September. My levels were down at zero last week. However. My last pregnancy I got symptoms a few days after sex as well. My nipples are sore and I have the feeling of gas in my uterus. As I did previously. I’m hoping it’s my period as I’m only 16. The guy was a bit older than me as well and it’s just not what I need at the moment. I know what I’ve done is stupid. I keep making stupid decisions. I just want some insight with no judgement. Thank you.