Unicornuate, Low egg count

I'm 42, just married: I learned about 14 years ago that I have a Unicornuate Uterus. (unattached mass on non-working side)
About 2 years ago, possible fibroid, but non-invasive.
8 months before marriage, egg count (FSH?), a little out of range, but still available for a drug to help with egg count.
Now: I believe my FSH is a bit out of invitro range and the dye test seems to have indicated there is no outlet from "working/existing" fallopian tube, may not be so open to ovary. OBGYN will not even offer the drug.

I still have periods, very painful but very regular. I'm under the impression I'm not a good candidate for Invitro.
I'm frightened as to what happens if I still by some miracle, do get pregnant? I have heard of external (outside the uterus) pregnancies?? IF that happened to me, would preg-tests show negative and still get my period??

Also: Some guidance: being unicornuate-where does everything go-my period being so painful?

Thank you for any help.