Bfp after period and at 17dpo??

Jen
I'm in search of some advice
​So AF visited last week. That was 9dpo and lasted for 5 days and a day of spotting at the end. Two days later I started spotting again and feeling cramping and crapping. I had taken a pregnancy test the day after AF came just for the fun of it and it was negative. I took an opk today and it came back as a faint positive. Well today after talking to my sister about how I was feeling she suggested I take a pregnancy test. The first was an internet cheapie and it was negative. So I decided to take another that was a different brand and it was a faint positive. And then I took a digital and it said yes. This would make me 17 dpo if that wasn't actually my period. Obviously I need to book an appointment with my doctor tomorrow. But has anyone ever experienced this before? What does it mean? My sister had a cyst rupture and had similar symptoms before it ruptured so I'm nervous! Help!!!