Hello, and welcome. I'm sorry that you find yourself here, but please know that you aren't alone. I'm not a doctor so I'll do my best to explain based on my understanding though I am sure there is way way more to the story.
They can see the follicles in your ovaries through a transvaginal ultrasound. Not all of them, but the ones that are 'ready' to develop. Most people have between 10 and 20 that are visible on any given cycle, which is called their AFC. If the cycle progresses without medication then one or two of these would grow/develop and ovulate. If you are given injections to promote egg development then roughly 50-100% of them will grow and develop and can be used for IUI or IVF. People with low ovarian reserve have a much lower AFC. Mine is 4 most months. So even for me, if I do get the stimulation meds I only ever get 2 or 3 eggs that can be retrieved, which is considered bad enough that they won't recommend using my eggs. So if they really didn't see any in your ovaries then that would certainly be very telling. You could ask for them to look again next month. They would only need to do it once, around cycle day 3, to either see if they see anything, or they don't. But if they have already done this on more than one cycle then that might be all they can do. Unfortunately, the injections can only promote egg stimulation for the eggs that are there, and visible at the start of a cycle, so if there are no eggs visible, then the injections can't make them appear. Just like when I cycle, if I started with 4, best I could ever hope for is 4. Again, this is only my understanding. Have you had a chance to talk to your clinic's doctor about it? They should be able to explain these findings, their implications, and your options to you in much more detail.
In regards to an underdeveloped uterus, I'm sorry I've never heard of anything like that. I imagine that each case is different in terms of how underdeveloped it is and what that means for carrying a pregnancy.
Infertility takes us to all kinds of interesting places that we didn't think we'd go. There are way way more options today that even 10 or 15 years ago. And certainly more than 20 or 30 years ago. But with that comes more questions and more emotions. Babies are brought into the world through all kinds of magical ways, and when you're ready, talk to your clinic about which of those options might be important for you to think about. After multiple losses, and very low egg production we were able to become parents through the gift of donor embryos. Donor eggs, surrogacy, and adoption have all been things that we pursued, or considered at one time or another in the process. Whatever path is right for you know that you are not alone. There are many members of this site who have experience with all of these and much more.
Best of luck to you as you try to find some answers and some options.
I am 38, DH - 39
Genetic - IVF&PGD to prevent Genetic Disorder
IVF #1 - Nov/08 - MC @ 6 weeks, no embryos frozen
IVF #2 - Aug/09 - bfn
IUI #1 - Feb/10 - ectopic
PRIDE - Apr/10
Homestudy - July/10
Given the gift of donor embryos - Jan/12
Donor FET Jun/12 - 9 weeks - no heartbeat... MC
Donor FET Oct/12 - we're PG
===> Beautiful baby boy born 2013
Donor FET Oct/16 - chemical
April 2017 - surprise PG
===> Beautiful baby girl born 2017