One of the common side effects is weight gain but usually modest activity will counter the weight gain. If you are beginning to reach the maximum dose of the TCA then likely you need to switch to another medication. Your headache sounds like tension, chronic type. I am not really sure what the paresthesias are from. Likely, you have a mixed type of headache.
Blocks can work, but usually they are tried after other medications have been tried.
Maybe a calcium channel blocker might help, if the TCA has been maximized. There is an excellent headache physician at Thomas Jefferson in Philly. Although the train ride is long, it would be worth your effort to visit him, he is one of the best. Best of luck with your headache. All rights reserved.