There can be several reasons for not conceiving , most common cause in your case seems to be ovulatory factor , you should go for follicular study
on 11th and 13th day of cycle to see the maturity of ova under USG after consulting a gynaec.If the size of ova is less then 19mm your doctor will give you some injections like FSH but do not take them without proper guidance , before that your husband should go for the semen analysis
.You should get your Endometrial biopsy
done before your spotting to see the secretory phase . You have to take progesterone
for luteal support.HSG
is another test to see the tubal patency.Then there are certain immunological tests also.