Let me give you some insight into what is going on with you. Start by recognising that you are not you mind.
Mind is like a drunken monkey (Vivekananda). It never behaves rationally. The advice which will work 100% is to take care of your body. In a sound body, resides a sound mind.
- Go physical. Work out will clear the toxins in your mind an your mind will stop shelling those negative thoughts to you. You will not realise the power of work out unless you try. Your mind will surely repulse the move!
- Go out deliberately . Yes hang out with friends or may be alone. Take a picture of you daily and see the change in your persona. Mind believes 90% of things which it sees.
- Write your heart out. You have already asked the question, hence 60% of your worries will melt away if you reread your question at least 2 times per day for one week. Mind is a machine (Organ) which always seeks reason for every thing (Confirmation Bias). When you reread your problems, it will seek different reason each time and ultimately will start seeking positives out of this.
- Think long term : Research shows that thinking about long term goals always bring you out of present negative situation. Write down your long term goals and design a brief plan for it.
- Smile and wear sunglasses : Again proven in clinical research that smiling often (May be deliberately) will signal your brain that every thing is fine. Same with wearing sun glasses. We wear sun glasses when we are in a light mood. It kind of rekindles the ‘happy memories’ of brain.
- Music : Listen to the music from your happiest times. Rock (Pop,jazz,metal beat,fast) does wonders of mind health. The lyrics must be minimal and beats must be maximal.