Maybe, if you were further along than you thought. I'm pretty lean myself and didn't feel anything until 16 weeks. Even then they say typically you don't feel anything until 16-25 weeks. Maybe even 13 weeks you might start feeling something. They didn't do a dating scan on you?
It could be feeling blood rushing if the placenta is more anterior. Or even muscle movement to accommodate a growing uterus.
I don't have an obgyn yet. I'm waiting for a referral from my doctor. I didn't find out I'm pregnant until about 3 weeks ago and it's because I got so sick I couldn't do anything but it only lasted a week
With my first I didn't feel any movement until I was 19 weeks. This is my second and I'm only 10 weeks and I haven't felt anything yet and I probably won't for a few more weeks.
I felt slight movement with all 3 of mine at about 18 weeks... unless i layed really still for ages then i felt it. But generally 18 weeks where id distinctively know he or she was moving xx