hii.. i have gone through your query and i understand that you were trying to get pregnant since june. you said you are three weeks late on your period it doesnt necessarily mean that you are pregnant particularly after getting negative pregnancy tests. you were diagnosed with PCOS and i want you to know some details about it. PCOS patients usually have irregular periods and hormonal imbalance which might lead to infertility. some people might not show any symptoms except for not getting pregnant. If i were your treating doctor i would suggest you to get re-evaluated. get some hormonal tests like FSH, LH, AMH(Anti mullerian hormone) levels. if these hormone levels are good then there are more chances of you getting pregnancy spontaneously. if there is any hormonal disturbance, it can be treated and you could get pregnant with some medicines easily. So, i would suggest you to consult a gyn&obs specialist or an infertility specialist and discuss about the tests and treatment plans. i do understand it all sounds a bit scary bt do not worry as PCOS has become most cause of treatable infertility in many women. hope my answer helped. please feel free to ask me any doubts you have regarding this. goodluck.