Hi Ss, I know you are at a negative point but what vossy said is true. These WAS spout all kinds of stuff. Maybe it is true, maybe it is true in the moment, and maybe it is complete nonsense. Try not to listen to it.
The typical ways to break out of a funk you already mentioned, like go for a walk, watch a funny movie, etc. But for me the best thing is just to feel really sorry for myself, cry my eyes out and go to sleep. Later things are better.
Vent to us on here, write in your journal, watch a sad movie and cry. Feel the pain and it will pass. Watch The Fault in Our Stars. What a touching movie. I cried a lot. On the airplane... haha.
Things will improve, and especially your mood will improve. I promise!