I may have been pregnant with twins? thoughts?

Ge
I found out I was pregnant BEFORE my missed period (I had implantation bleeding and thought I was getting my period a week and a half early. After some spotting I tested several days later) and it was super positive. Like even showed up positive within a couple seconds instead of the three minutes or whatever. I started bleeding about two three weeks later, bleeding that increased as the days went on and I had bad cramping. When we went for our ultrasound they said I looked like I was only 7 weeks or so even though I'd been tracking and knew when he was conceived. I have a healthy son now but I can't help but think he was a twin and we lost the other. I've thought this since we had our first ultrasound and throughout the whole pregnancy and even to this day. Obviously there's nothing I can do and I'll never really know but what do you ladies think? Any experience?
I know it's random but I just saw a post of a very positive test and people were suggesting twins and it got me thinking.