Welcome to the forum and I am so sorry you are feeling so badly both with depression and intense headaches. Nothing is more debilitating than pain especially when the origin of the cause is not known. You also seem to have a most unsympathetic Dr! But you are correct to a point that many of them are very shortsighted when dealing with the after effects of the surgery. The surgeon cuts,,, he doesn't always do the best at following up with post symptoms.
Did you have an ENT (otolaryngologist) on the team for the surgery? If so, and I hope you did, you should be seeing him/her for follow up also. This might be where you could get more empathy for ongoing problems. If not then maybe you should see a neurologist in case it is something else. At the very least, either of these Drs might be more sympathetic and prescribe an RX for depression or refer you to a psychologist to listen to you and help.
Please don't give up on recovery and healing! These surgeries are NOT like a broken bone that heals in 6 weeks,,, this is brain surgery and the brain demands time to heal from the "injury"!
Please get some help,, somewhere,,, it is so necessary to know yourself and your unique needs. You may not be able to pull yourself out of this without help, either meds or temporary therapy. But it will get better,,,
We care here and have you in our thoughts and prayers,,, please stay with us and let us know how your headaches and how YOU get,,,,