When i got sad of something, or anything not desirable happen, i got a severe headache in the part beside my left eye, and it makes it harder to do things like even talking or do activities, literally everything, it may last for months?

It is not feasible to provide a meaningful opinion without taking additional history, physical examination and may be some tests. It would be prudent to see your doctor and discuss if you may be depressed. Counter-intuitive as it may seem, exercise may help. Start with low intensity exercise such as walking and gradually increase the intensity as tolerated. Drink more water. Wish you good health!

Certainly address your emotional changes, which could trigger headaches, but appears these too need direct intervention. Cognitive-behavioural therapy will help and biofeedback therapy has helped many with headaches. Both therapies might obviate medications.

The pain on the side of your head is likely the temporal chewing muscle form the stress of clenching the teeth. Behavioral modification and possibly a TMJ examination are in order.