Move your body if you can, light to moderate exercise, even just going for a long walk is the absolute best non-medical treatment for depression. Your body makes a bunch of the feel good chemicals when you move that depression deprives you of. Also a change of scenery can help a lot. If there is a place you’ve wanted to go nearby like a museum or a park or something that can help you start to process and move on from a bad relationship end.
I live somewhere very hot so when I get like that, every other month or so, I go to a shopping mall and walk a few laps in the air conditioning and watch all the people. Your mileage may vary but walking around in places with a lot of people helps me.
It also might not hurt to talk to your provider about adjusting your medication if you feel like you are for more than a couple weeks. The most important thing to remember is that states like these are temporary, you have felt better before and you will again on the other side, you just have to get through it.
I’m the same way when I’m down. Nothing anyone could say seems to apply to me and I’ve always got a logical, (mostly) rational reason why. Depression is weird like that. I’m bipolar so I’ve done a lot of therapy and tried a lot of medications but none of it really sticks when I’m at the bottom of the cycle. The advice I offered was stuff I had to figure out on my own the hard way, but it was not something I invented. It was little bits and pieces of things therapists and confidants had shared with me over the years that eventually clicked.
But the only truth that matters is that the only way out of it is through it. You’ve got to find the things that work for you because we’re all different. It’s about taking care of yourself first and foremost. I rationalize and use research about neurochemicals and mindfulness to stay afloat, you might find something else that works better to help you cope. All you have to do is keep trying and eventually you’ll find it.