There are some things I do is when I'm anxious, or memories from PTSD come up that I learned in group therapy. One: when the bad thoughts come up. Realize the thought, write it down in a notebook and let it go. Two: staying present in the moment. Take a breath in and count to 5, let it out for 7 seconds. While doing this pay attention to what's around you ex: the music playing noises out side ect. Three: for depression keep a journal for things your grateful for every day. A second journal for complements people have given you every day. Whether you believe them or not, or from a complete stranger. One last note, surround your self with people you trust and dont isolate your self.