Bad Place

I just got the results from my third IVF cycle yesterday, yet another NEGATIVE!  I really am not in the best place right now.  I have no idea how it can be so hard for some people and so easy for others and quite frankly, I'm pissed about it!  This IVF cycle was with a new doctor and I really thought he could make it happen!  He retrieved 12 eggs, 10 fertilized (which he said was really impressive), 9 kept growing and somehow I ended up with 2 "excellent blastocysts" on Day 5.  Sadly, none of the others were good enough to freeze, but I was still hopeful those 2 "excellent blastocysts" would do the trick!  I was told there was a 50% chance that they would result in one or 2 full term pregnancies and that that was about as good as it got!  Nine days of Crinone, Estradiol, Estrogen patches and Progesterone shots later and I get a voicemail telling me I'm not pregnant and I can stop all my meds!  Again.  Honestly, I'm not sure how many more times I can go through this.  It's trying on so many levels, emotional, physical, mental.  Every month, I do all that is asked of me by the doctors and the nurses, I try to maintain a positive mind set which ultimately leads to me believing it worked and then being let down.  AGAIN.  How much is enough?  How many times do I keep doing the same thing over and over before I realize it's not going to work?
I started this year at a fertility specialist, feeling like this was going to be my year.  And now, this year is almost over and I am at exactly the same place I was when it started only with less money and less hope.  I think I'll finish the year with one more IVF and then I'm done.  If it doesn't work, I gave it my best shot.  I gave it all I had.