IUI cancelled and I'm feeling hopeless

Emily • Married in 2010 and are ready to become a family of 3! TTC baby #1 since June 2014. Wish us luck!
My hubby and I have been TTC for almost 3 years. We have been through every test known to man and everything has come back normal for both of us, leaving us with the diagnosis of "unexplained infertility". You'd think I would be happy about this but it is more frustrating than anything not having an answer to why this is all happening. If we are both so normal and healthy why can't we conceive? It just doesn't make sense. 
 I did my first round of Clomid 50 mg less than a year ago with timed intercourse. I responded very well to the Clomid and produced five follicles, but for some reason I didn't get pregnant. They discovered a polyp in my uterus so I had a partial D&C in April to remove it. The doctor said to keep trying on our own and if nothing happened in six months then to come back and we will try <a href="https://glowing.com/glow-fertility-program">IUI</a>. 
So here we are, 6 months later. The doctor told us that with <a href="https://glowing.com/glow-fertility-program">IUI</a>, the risk of multiples increases so if I produce more than three eggs they likely will cancel the cycle. He put me on 100 mg of Clomid this time and when I went for my day 11 follicle scan, sure enough, I had overproduced again and had 4 follicles this time. They said this was too many so they canceled the cycle and I have to wait until next month to try again. DH and I are still having sex during my fertile window this month, even with the risk of multiples.
I'm worried because I have heard you can only be on Clomid six times because it thins the lining of your uterus and will not be able to support a baby. This was my second time so I only have four more chances. My doctor also said he only wants to try three rounds of <a href="https://glowing.com/glow-fertility-program">IUI</a>. If it's not successful he wants to do a laparoscopic procedure to check for endometriosis. Then our last resort is <a href="https://glowing.com/glow-fertility-program">IVF</a>, which frankly I don't think I will be able to do because my insurance doesn't cover <a href="https://glowing.com/glow-fertility-program">IVF</a>. I'm also wondering why my doctor prescribed double the dosage of Clomid knowing that last time on 50 mg I still produced too many follicles. I'm sure he knows what he's doing but I'm hoping that this doesn't keep happening. 
This whole situation is incredibly frustrating and heartbreaking for me. It's so unfair that people with infertility have to go through so many painful and expensive medical procedures just for a chance to POSSIBLY have a baby, when other people can just have sex one time and get pregnant right away. 
Does anyone else have any experience with this or advice to give? I wonder if there's a different type of medication besides Clomid that would work better since it seems like Clomid works a little TOO well for me . I'm starting to lose hope because I feel like I'm running out of options if this doesn't work. Thanks for any advice you can give in for just letting me vent. I wish you all the best of luck!