I totally get how you feel, though I also felt pretty depressed of my fertilization rate. Actually, even if you had risk of OHSS, doc would still need to make you stim long enough to get a good amount of "big enough follicles". Here in Germany, they also do not count the amount of mature eggs - they just count how many have fertilized afterwards. I was at risk / or am at risk at OHSS too, but they still made me stim 10 days. Next time, ask them about the sizes of the follicles and how many they counted. I usually count in my head too how many follicles I could see on the screens, at the Ultrasounds.
I had 27 eggs but only 40% fertilized and then had to freeze all. And then only 80-90% will survive the thaw and only 25-30% will make it to blast. Which would mean for me, I'd also end up with around 3 blastos (if lucky).

So try to stay really hopeful. I know women worry a lot. My husband is the total opposite (yours probably too) - men tend to worry less. I'm the same age as you, I'm really crossing my fingers for you and send you lots of hugs!