I also have PCOS and possibly thyroid issues as well as being overweight.
I never responded to Clomid.
What finally worked for me was using the Follistim injectables (I started on day 3-4 of my cycle and just took the doses that the Dr. would tell me to take...as he'd do ultrasounds and see how I was responding every couple of days and then take the ovidrel shot when I was ready to ovulate). I also took 1500mg timed released Metformin every evening as well as a prenatal vitamin.
I was about 265-270lbs during my last couple cycles and I'm 5'8.
After my two pregnancy's/miscarriages I contemplated taking a year off to try and loose some weight.
But I sucked it up and tried one more time...and it was again a

, this time with twins. We lost one of the twins early (vanishing twin) but we're currently 26 weeks pregnant with a precious little boy.
I don't regret TTC and conceiveing while being overweight. I've struggled with weight all my life. I wasn't willing to put off TTC any longer, just to loose weight...when the injectables could help give me the exact hormones I needed to finally get my ovaries to work.
I love being pregnant and love my growing baby belly. Infact I'm feeling more womanly and sexier than ever and proud of my body...which I haven't felt for over 10 years now.
My Dr. has never mentioned ANY concerns regarding my weight and the baby or pregnancy. So far all my insuline levels have been perfect as well.(which I was a little afraid of when they took me off the metformin....but I wasn't put on in for Diabetes...just to help me get pregnant).
I do plan on trying to loose weight after the baby comes. But now (with this pregnancy) my life is feeling more and more complete and I feel like life is really just begining for me.
I say...don't put it off...go for it now...you have the rest of your life to try and loose weight...and you can try and start loosing weight now...by just eating healthier and drinking lots of water and starting a light exercize routine.
It's much easier to watch what your eating when your TTC or pregnant...because it's not just you that your feeding...you try and make every bite count...and as healthy as possible.