High HCG

I should be about 4-5 weeks after conception but 6-7 weeks pregnant since they go off the start of your period or whatever. Yesterday I started cramping and having light bleeding so I had my levels checked today for peace of mind. My levels were 17,300! According to this the weeks are listed in “weeks after conception” so this would be crazy high.. I don’t think I’m further along as I had taken a test 4 days before I got my positive and it was a hard negative. Any one have any insight? Twins? Am i reading it wrong? I have no idea. 😅