low beta and health pregnancy experiences please

So today at 10 dpo I had a beta drawn 4 hours later the results came in at 18 the nurse said the numbers are okay concidering I'm only 10dpo they want to see them minimum of 36 for Thursday which is when I go back in I keep over thinking it thinking that I'll get them and they won't have rose or that there going to tell me it's a chemical ... has anyone had experiences with low betas early on and gone on to have a healthy pregnancy