9 weeks out frustration

I am 9 weeks out from my surgery... So far I've lost 40 pounds & am very happy with that. However I am feeling frustrated & don't understand why.  I've been told I'm hitting the depression phase.  I go back to the doctor next week & know I need to ask questions but don't know what to ask!  I'd appreciate any advice I can get.   I've struggled with protein shakes, finally have that worked out ( I think)  now my hair has thinned  out  A LOT & that frets me too.  

I just needed to vent some... advice is welcome. Thanks!