Answer:
despondent
Explanation:
Sam Houston was feeling despondent because he was leaving the Union, and the Union has helped him overcome many obstacles, and has helped him, and they kinda became like a family to him (well that's what my teacher said). So leaving that "family" makes him despondent because it's like losing a part of himself. But even though he is leaving the Union, he is taking a big part of what the Union has helped him with, for the near future.
Hope this kinda helped!
Have a supercalifragilisticexpialidocious day!