I've been through terrible times in my life, so when things are not so great right now, I just remind myself that things have been much much worse before (I still get scared/anxious, but I remind myself of past times and I still remain eternally grateful that my life is not in the same place that it was many years ago.), and I also take warm baths. I have many Kneipp bath soaks at home (I love the purple one for a good night's sleep), and I use those. Also, retail therapy + regular therapy + medication. (Just saying what works for me. I am not advocating the use of medication for anyone, but I have actual problems from the past that I won't post on here, so for some, it is needed.)
You'd be surprised at what regular therapy with a good therapist can do. It might take you a while to find a therapist that really works for you, but a few sessions of really just talking about your problems to a random stranger can work wonders. You don't have to commit yourself to someone and it's not always for people with real problems, you can just go to one or two sessions when you feel like, you need to talk about life. I don't have friends, really (partly by lifestyle and partly by choice), I'm sure that my SO, even though he would hear me out, doesn't want to listen to my problems all the time, so I find that sitting down with a stranger and telling them about what's bothering me, really helps.
Also you can try going outdoors. If you don't have a porch to hang out on, you can go for a walk around the neighborhood. If you live around a bunch of busy streets you can try to take the back roads and just go for a walk across the town. Sometimes walking outdoors can make you feel a bit better. Or you can try walking in cemeteries and parks.
Also what works for me is keeping a book, or a journal. (Not like the kind that you would keep as a little girl.) And if you have negative thoughts or you're having a bad day, just write about it. You can write all your negative thoughts down, and this also helps you feel like you're getting your thoughts out there without, say, unloading it all on your roommate, best friend, or partner constantly.