cramps early in pregnancy/hcg levels

I tested positive at 10 dpo and had my hcg levels drawn. It came back at 29. My doctor called me today to tell me they were a little low and to test again 48 hours later. I do have mild, intermittent cramps that remind me of AF cramps. I have so much anxiety about my "low" hcg numbers and now mild cramping. Has this happened to anyone? Has anyone had an hcg level around the same as mine and have a healthy pregnancy? Are cramps normal in easily pregnancy? I am hoping the low numbers is simply because it is so early, I haven't even had a missed period yet. I know that I just have to wait to find out if my numbers doubled but would also like a piece of mind if this has happened to anyone else. Thanks!