baby
This post is for you. I am not an expert but this is just to guide you along.
As the others asked, have you seen a gynae/TCM regarding your irregular menses? I think what most ladies here do is take BBT or use OPKs to find out our ovulation day and then BD to maximise chance. Some also see TCM to tiao our bodies or take supplements like Conceive Well or Bai Fong Wan to regulate the cycles.
Btw, doesn't mean have menses = got egg = can get pregnant. Coz to get pregnant, you will need to ovulate which means that the egg has to be released for fertilisation. You can have menses even if you don't ovulate (i.e. the egg didn't release for fertilisation) and in this case, you also cannot get pregnant.
This is why we ladies here use these home testing kits (BBT and OPKs) as around ovulation, our bodies will produce a hormone called LH and the LH surge before ovulation lasts from 24-36 hours. This is probably the best time to BD-ing "intensely" (but with 24 hours interval between each BD) as once egg is released, the egg only lasts for 12 hours. The other way to confirm that you will ovulate is to see a gynae and scan for the egg but this will be quite expensive (around $100+ per scan) so we take the cheaper alternative of testing at home.
Hope to have helped and welcome to joining us in our TTC journey!
P/S:
Just to help you, BBT = Basal Thermometer, OPK = ovulation kits, BD = s**