Ectopic?

So I recently went to the er for sharp pain in my left side. They drew blood and did an ultrasound I was 4 weeks and about 5 days they couldn’t see anything on the ultrasound at the hospital other than a cyst, a few days after I got repeat blood, I am now 5 weeks and 3 days and hcg more than doubled to 4402. I have a repeat ultrasound in a few days. Has anyone experienced this? Should I be concerned?