Irregular period?

Peyton • Southern by the grace of God. In love with an Airman ❤️✈️
I just got off a 7 day period on Sept. 6th. Had unprotected sex on the 10th. And it's now the 11th and I've started my period again. Few minor cramps (not as bad as usual), foot cramps (hurts to walk, weird cause it never happens), and lower back aches. I was on the pill for about 6 months but got off a few months ago and had no problem getting off it it. I got on the NuvaRing a month ago and didn't like it, so I got off of it this month. Idk if my period being so close together is because of BC (but still doesn't make sense considering this has NEVER happened) or something else. Please help!