Trigger Shot Tonight

Today is CD10 and I had an ultrasound. I was on letrozole and menopur and have produced one 18mm follicle on my right ovary and two follicles, 18mm and 17mm, on my left ovary. The doctor told me about the chances of multiples and gave me the option to go ahead if we choose to. Well we chose to still go ahead knowing the risks and trigger tonight with the IUI Thursday. Anybody have success with numbers like these? I will also be taking progesterone after the IUI. My trigger shot is pregnyl, is this worse than the menopur with the burning and stinging?