Clomid or Letrozole

I️ had an ectopic pregnancy and my periods were irregular since. Come to find out I️ do not ovulate so my OBGYN prescribed me Letrozole. I️ took it the first cycle and still no ovulation. I️ just recently started taking Maca to see if it would help. However I️ just seen another post where a lady said she didn’t ovulate and her OB prescribed her Clomid. Just curious to know the difference between the two and if I️ should ask my doctor if I️ should switch if I️ do not ovulate the second cycle around.