Could my pregnancy be ectopic if they can't find it?


Hi ladies! I'm pregnant for the first time and really scared because I'm high risk for ectopic pregnancy. I'm 6.5 weeks by date of LMP but I ovulated late (21 days into cycle) so I'm reality I'm like 3.5 weeks pregnant. I have endometriosis and PCOS and had 3 prior surgeries. My doctor made me get 2 ultrasounds already when I was barely even 6 weeks and they can't see anything yet. My HCG level just reached 1389 and has been doubling every two days normally. I'm going for another one this weekend now that I'm 6.5 weeks but I'm scared to death. I've spotted brown and pink on and off, I feel a little cramping and stretching in my abdomen and on the inside of the top of my thighs, and also have on and off lower back aching. I'm on a progesterone supplement (Endometrin) because my progesterone level was declining (went from 13 down to 10) but is now back up to 16.7. Should I be nervous if they don't see anything on this 3rd ultrasound. I'm scared my doctor is going to try to terminate my pregnancy simply because he can't locate it (and I won't let them do that). Advice please!