Early pregnancy? Normal? Ectopic? NEED ADVICE

Hey guys so I recently found out I’m pregnant. (I’m guessing I’m about 4 weeks)

Now, I went in to have it confirmed, however my blood test showed my levels were at only 140. So they had me come back in 48 hours later to retest. They were then at 211. The next day (about 12 hours later) I went back and they had more than doubled from 140, to 321.

On the ultrasound it showed nothing in my uterus, but nothing in my tubes either.

They want me to wait another week before I go back, but I’ve been having twinges of “pain?” In my right side around where my ovary would be. Sometimes it happens on my other side too, but not as bad. They’re sharp pains but very light, like twinges kind of, almost like ovulation.

I’m just really scared and confused and I need some words of wisdom to calm me down until my appointment in a week. My SO is out of town at work during the week so I’m alone most of the time and my brain drives me crazy. Has anyone had this happen and it be a regular pregnancy? I told my doctor about the weird pains but he doesn’t seem to be concerned too much. However I’m terrified. Help?