Why Am I Not Able To Conceive Even After Taking Clomid?

Hi My name is Anitha and I am 30 years old and weigh 53 kgs and 164 cms. I had problems in ovulating and for the last 2 years I have been trying to conceive. I have checked with doctor and they advise me to take clomid and kept observing the changes. I ovulated between 12th to 14 day and hence continued the tablet for 5 cycles however I couldnt conceive. Later the doctor advised to change the tablet to Letroz 2.5 mg and I continued to take the tablet from day 2 to day 5 and done the same now for 3 cycles however stil not been lucky. I have checked the fallopian tubes and the report is fine. Could you advise what could be the reason for this. I am married for 4 years and never been on any birth control pills. I am realy fedup of trying. I do not know the problem with me. I had problem with the FSH and LH levels being high as such the both were same levels hence doctor put me on medication for ovulation and thats it. Please help me.