I am around 120 pounds overweight and I concieved. As a matter of fact I'm 25 weeks tomorrow and I've only gained 5 pounds. (well, maybe more after days of Christmas faire.)
Don't let what the doctors say make you crazy. Now, I don't have PCOS, but I know PLENTY of overweight women with PCOS that eventually concieved. There were countless times in the time I was TTC that I prayed I'd had PCOS because at least that would have given us something to go by instead of "unexplained infertitlity." I TTC with my first husband for 7 years. Did 9 IUIs with Clomid and Femara and not one worked. My husband was fine and I was fine. ANd then at some point my husband stopped producing sperm for no reason. We even did two IUIs afer that with donor sperm to no avial. Then my husband left me without any warning. It was horrible. But I continued to TTC with donor sperm for months -- and then had a live local donor I was getting it from and nothing worked. Then I "hooked up" with and started dating this man I'd known casually for about 8 years.. in ONE FREAKING MONTH we were pregnant. Our baby girl is due TWO WEEKS short of the *10* year anniversary of me starting to try to concieve. So I am here to tell you that all is never lost. Now I'm not going to say I wasn't a complete crazed maniac about it for 10 years because believe me, my friends, family and co-workers delivered 52 babies in the time I was trying... including my roommate having TWO while living in my house. You just have to kind of try to get by. Try to be happy for them because if you aren't, eventually you'll feel guilty about it and guilt never helped anyone. I did stop going to baby showers -- and all of my friends were fine with that. There were many that didn't tell me they were pregnant until they just couldn't hide it anymore... Many waiting to see if maybe I'd get pregnant in the meantime. I spent a lot of time crying, a lot of time screaming into my pillow... but in the end I guess what I really want to say is NEVER GIVE UP HOPE. But at the same time TRY to not make yourself insane. I was pretty darn sure I'd never be able to concieve my own child when I started dating Jason ... after all, the sperm of four different men and lots of hormones and medical supervision hadn't ONCE done the job... but I guess in the end it just wasn't right. I'd also started the process of trying to adopt a teenager from the state because that's the only way I could afford to be a mother... but put it on hold after starting dating Jason because I knew it was going to be serious from the beginning -- glad I did!
You're not alone. And I know nothing anyone can ever say is going to give you any sort of comfort -- but I know through all of the time I was suffering I'd heard 5 years and even up to 8 years of people trying before anything worked -- but never 10. Never once did I ever hear anything that would give me hope even close to 10 years. So I just hope my story will give you some little tiny bit of comfort. It'll happen... as long as there is hope. Even with a few extra pounds!

And PCOS in my experience (of obsessing over trying to get pregnant on message boards over the past 10 years) is highly treatable and not as big of a hurdle as you might imagine. It just makes things a little more interesting.

Take comfort in the fact that you know what's wrong and that there are ways to get around it.

It could be worse.
As for the concern about losing the weight -- they tried to pull the "you have to lose weight" thing on me... I went out and lost 40 pounds -- and didn't get pregnant. Of course I did feel a lot better about myself for a while... until the ex husband left. Then needless to say the weight came back.
Just my $.02. I hope it helps.