Had a 16mm follicle when ovidrel was given. was it given too soon? will there be a delay in ovulation despite the trigger shot?

Of course: the best person to be answering this question is your treating infertility doctor. Most experts would say that the ideal follicle size associated with maturity of the egg is 18-20 mm or larger. There certainly could have been other additional factors leading your doctor to administer the hCG. My understanding is that once the "trigger" hormones are given, the egg will be released/ovulation occurs.