is it my inability to have a positive attitude?

Today I started to wonder if we should switch fertility clinics. When we were doing IUIs there (I think we did 3), one of the doctors told me that with my age and labs, we had an 80% chance with IVF. Great, I thought. If it doesn't work the first time, then it will work the second time. We went ahead and did it and I made a nice number of eggs (with subtle suggestion from the stimulation drugs). It was all playing out very nicely until the 2 transfered embryos didn't take. I started to think I just wasn't a good vessel (as far as I know, I was only pregnant once for about a week even after years of stupid contraception mistakes). At the first transfer of fresh embryos, the doc said that there was a 50% chance (not 80% but still great odds, much better than I could do on my own). At the second transfer (3 frozens), the doctor (a different one from the first transfer and from the 80% stat) said that she had a very good feeling about this. She didn't say it, but I heard 100% in her tone. She had also previously told me that she thought I would get all of the kids that I want from this big batch of eggs/embryos that we made (I am a hen, I have learned). Well, the second transfer didn't work. So, let's see. I've had 5 very nice looking day 5 embryos transfered. From the 3 IUIs (with clomid ovulation induction), there were probably about 5 more eggs that had some chances. I am 0 for 10. When I first started suspecting that something was up (and when I cared to do something about it - these are different), I read that even in 'normal' couples in my age bracket, there is a 1 in 4 chance of conceiving naturally. At what point does this become a problem with me? 0/20 (this will more than max out what we have in the freezing nitrogen)? I am confused and a tad bit annoyed with the doctors. I'm going to investigate others because I refuse to give up hope even though it sounds like it, huh?