What’s going on?

I got my period January 28th-February 5th and February 25th-March 3rd. But I got a positive pregnancy March 5th and my hCG level was 16. Now, March 20th my hCG is at 1,300. My expected period is March 25th. Do you girls think I’m having twins? Due to the high hCG level at this time and the early positive hpt? I have a family history of twins. Also, they thought I was 5 weeks but they can’t see anything on an ultrasound yet. So I’m thinking I’m just early along with twins but I don’t know.