I completely understand your feeling, it happens to many people at a certain point in life. Even I was in that state, I hated myself and my life to the core. If I am happy, the next moment all of sudden, I use to feel like crying loads. The best way to feel better is to stop overthinking, keep calm, start loving yourself, start loving the life God has given you, stop expecting from others for a while, keep yourself busy in other activities, do things which you like. If something happens wrong, try to figure out positive things out of it so that you can correct, don't let negativity dominate your positivity. This worked for me. Might work for you too. https://esacare.com/role-of-esa-in-treating-psychological-disorders/