Low Progesterone and irregular ovulation

I went for my yearly today and after 7-8 months of TTC, most everything looked normal.... Good news. Given the lateness and sometimes earliness of my periods my OBGYN thinks I had low progesterone levels causing me to not ovulate regularly. On day 21 of my next cycle he is going to test and start Clomid. He says "it's and easy fix". Is that true, any experiment with similar situations?!