Femara

After having an IUD for 7 years & thinking my periods were on track after removal in Sept- they aren't.  It's been all over the place & I never got a LH surge this last month.  Plus my last 2 periods were so light I didn't even need a liner.  Plus they were 22 days apart.  Really irregular to say the least.  My OBGYN doesn't think I'm ovulating & so he's planning on starting me on Femara when I go in for my apt on the 16th.  Very nervous about it!  Anyone been on this?  Success stories?  Advice?  Thanks!