1. Write it all out in a journal or diary and let it all out in writing and tears, sometimes crying does help.
2. Watch a sitcom like "Steinfeld" or "The Office". If you're too broke for Netflix no worries, just write the title of the show or movie on google with 123movie. e.g. "The Office season 1 episode 1 123 movies". Just remember to quickly close the pop-ups.
3. Avoid having comfort food, it will just make you feel worse after it is all done. You know you're not hungry, just drink A LOT OF WATER!
4. Cuddle with your pet if you have one.
5. Clean your room and perhaps your house. My personal favorite is vacuuming and mopping my entire house.
6. Write a list of all the things you are grateful for and think about all the happy memories you've had in the past.
7. Listen to music that will make you feel good.
8. Go for a walk and enjoy the nature.
9. Realize that you can use this sadness, to work harder toward your goals and make it the medicine to work harder. Use this to devote your time towards your hobbies. e.g. drawing, bullet journaling
10. Talk to a friend and try to help them stay positive if you don't want to talk about your problems, no worries, you making them feel better will instantly make you feel better.