HCG levels

I’m 5 weeks pregnant after having an ectopic pregnancy last year and have been having blood tests done every 48 hours. My first test on Monday shown hcg level at 112, Wednesday was 242 so I started to relax a bit. Dr said it wasn’t indicating another ectopic so I felt a lot less scared. Friday’s result was on 439 so it hadn’t doubled and now the Dr said he can’t rule out ectopic. Of course now all the worry and stress has come back. Every twinge worries me and I’m just waiting for it all to go wrong.