Cyst or ectopic ..?

So today I went to the ER with some sharp left side paint. I am 4 weeks 3 days pregnant. The doctor did blood work and it went up to 4000hcg from 1295 48 hours prior! So yay.

During the ultrasound I saw a gestational sac in the uterus. However when the doctor reviewed the results they said there was a haemorrhagic mass in the left ovary (I have had haemorrhagic cysts here before) but because I'm pregnant they aren't sure if it is a cyst or an ectopic stuck in the ovary. I have to go back for an ultrasound in a few weeks, or sooner if pain increases.

Anyone had this before ? Should I be worried or just assume it is a cyst?