First IUI cycle

Hi,
I'm sort of new here. I'm sort of frustrated already and I am wondering if this is all normal.  My husband and I had been trying to conceive for over a year so my ob/gyn sent us to a RE. I had been on clomid before without insemination, but they discovered low motility in my husband's sperm. The first RE was more concerned about me but my only issue is that I have long cycles that are sometimes irregular (sometimes 30 days, sometimes 46). We are supposed to do the first IUI this cycle, and I took the 50 mg of Clomid on days 3-7 after the first ultrasound, then had a second last Saturday, then they said no sorry the follicles are not big enough, come back on Wednesday, so I did and I was only at 17 and he wants it to be 19, so I have to go back tomorrow evening (which wasn't all together easy to get the evening appointment even though my doctor told me that's why they have them for people who work) to see if it's big enough. My question is what is the normal size before the trigger shot that others use? When I was on three months of clomid before with another doctor, I usually ovulated around day 17-19 which is now, and I'm a little afraid it's going to just go on it's own. I expressed my concerns with our doctor (well the doctor who was in this morning) and was told not to worry about it and he seemed to think it wasn't going to go and if it did they would just you know do the insemination right then, not seeming to get that my husband has to be there and like today was on his way to work. Plus they only do the insemination early in the morning. But I usually know when I ovulate as I can feel the pains which I'm getting a lot of now. I just don't know what is normal and the driving back and forth every day to the doctor when I work is overwhelming plus I'm hormonal already so it's worse.

Thanks!