Needing thoughts

So I had my first appointment yesterday with my doctor. They drew blood to check my hcg level. She said it should double in 48 hrs. To come back on Friday to have it checked again. She also did an ultrasound to see if she could see anything. She asked if I was having any pain on the right side. She said she couldn't see anything yet. She said if I have pain to go to the ER because that could be ectopic pain. She said it was kind of early to see anything. I am 4 weeks and 3 days today. She has  me scheduled next Thursday for an ultrasound again. What are your thoughts lady's. Should I be worried?