Helpppp meeee

Ok so I need some help from u beautiful ladies who have been pregnant!! I was pregnant in April and told I was around 3-4 weeks. They said my hcg levels were really low and that I must be having a chemical pregnancy. I didn't have a period in May, but my period came back in June and in July. July 10th was the last time I had a cycle. After realizing I was late, I took two tests and they both came out strong positives. No faint lines, no guessing straight up, two strong ass lines ! But the thing that is getting to me and has me confused is that I have gained 25 lbs since April with no changes in my diet or excersise & I have stretch marks that randomly appeared on my stomach about 2 weeks ago. My stomach is noticeably bigger and round. The fact is just that there is NO WAY I am experiencing stretch marks & showing at only 5 weeks!!! Someone please give me some insight as to what might be happening. Could it be that my OB mistakened my low hcg levels for a chemical pregnancy and that I am still pregnant from then??? The only thing that gets me is my 2 previous cycles. But could that have been breakthrough bleeding? Somebody please give me some advice mannnn my doctor appt isn't until next Friday and my nerves are so shot over this !!