How long has everyone tried to conceive for before it finally worked?

I have pcos and been trying for a baby for three years now using metformin had a miscarriage last august but I gain weight all the time from my other disabilities and medication and I have to lose 2 stone magically in the next 4 months before I can try clomid. I missed mays period and last month I didn't come on either I had 1.5 days of very very light pink bleed last week nothing since, no period symptoms. I have nausea and fuller boobs I've always been flat chested but I seem to have boobs now in this past few weeks - a month. But tests say negative...