You as an individual are not responsible for who wins in November. We, as a country are.
Do what's best for your health and peace of mind.
But think about this, if you will: Who pushes the "they're all the same" (TATS) meme the hardest? IMO, it's often people who have an interest in things not changing in ways that you (and I) would like.
E.g. Ralph Nader - In his later political life, he had a utopian vision of the way the country should be governed and was against anyone who didn't see things his way. He was a purity troll. In 2000 he and the Greens had no plan for actually governing with Republicans or Democrats in control of Congress and the Senate. (I attended his "Super Rally" in DC in 2000 and may have voted for him - I don't recall.)
He had no interest in building a coalition or broadening his base - it was all about implementing his pure ideals. If things move incrementally his way, he loses his purity and thus the strength of his message.
On the other hand, some who scream TATS are like the professional Libertarians who are Republicans in leather jackets. They take advantage of the idealism of young people and construct arguments about logic and freedom and fairness that 90% of the time align with current Republican thinking on the major issues of the day. That's why their funding comes from hard-core Republicans like the Koch brothers. On those where there's a disagreement, it's on something like drug legalization that is utopian and will not be implemented for generations, if ever. So, by accepting that TATS, you're supporting Republican talking points and preventing progress.
You'll get a lot farther by writing to Obama and Holder and your representatives and telling them that you strongly disagree with their policies and explaining why, and will have more of an impact, than by getting angry and throwing up your hands - that won't get you anywhere. (Yeah, your letters may only move things 1 nanometer, but it's something productive.)
Hang in there and don't be so down! Think about the future and do your part to try to make it better for the unfortunate saps that follow us. :-)
Cheers,
Scott.