I think its fantastic that you met with ob and are trying things like progesterone. It all sounds really positive. But i have to say 19 months is not crazy long at all to not see af if you are still breastfeeding, though v.annoying. Give it a quick google and you will see the average is 14 months, often much longer. My baby was born in jan 2013 and af came back april 2014, this is totally normal- your ob should not have been shocked. Jan 2013-babys 1st bday i did cut back to bf only from 6ish in evening and once/twice at night-had him on cows milk by day from this point (+freezer stash). I also stopped pumping then, af showed within 10 wks of these changes.if ur bfing a lot, it wont come back-sends your body the message that your still nourishing one and not ready for another. I went on to bf in the evening and night until he was 23 months. Cycles were a bit irregular, some a few days longer than others but af showed every month and i ovulated every month. Hang in there, its probably coming soon!