Hi I Am Trying To Concieve For 3 Years Now,

Hi I am trying to concieve for 3 years now, I went to a gynae was diagnosed with pcos and put on glucophage with staminogro after 6 months I went back to gynae and was put on clomid 100mg with metformin.i had a 21 day cycle and after first cycle of clomid my period came on day 28. On second dose of I clomid I didnt get my period on 28 im one week late with no period and negative pregnancy test what is wrong with me, this is so stressful