Is it still so depressing?

So, I bought Fallout 3 a while back ago when it first came out and never completed it. Mainly due to the fact that it was physically draining for me to play. The terrible choices I was faced with, the mutants and giant roaches all wore heavily on my body (I am being serious). In truth, I enjoyed the game, but found it too depressing and draining to continue.

I want to play FNV, from the screenshots it looks great, more lively and upbeat. Is this true? Does anyone else feel drained after a Fallout session?