Help lol!

Me and my fiancé have been Ttc for 2 years now and nothing. I already have 2 children (that are not his) and 1 step son (which is his) and we want one more. For some reason we are having a hard time conceiving. I was on clomid for 6 months and nothing. And now for 45 days I been on this fertibella treatment. My doctors can't figure out whats wrong they even did a test that they Inserted liquid dye into my ovaries to see if anything was blocking them and he said there as clear as day. I have had irregular periods and withing the past 4 months they have became regular again. I just feel like giving up :/.