I beleive i can never be happy

Everytime life starts getting better something happens that utterly ruins me i got cheated on 5 years ago and that left me in a numb depressive state for 3 years i started getting better a couole years ago and i met this girl, she was amazing our first anniversary was yesterday everything was going great at first till she suddenly started crying and broke up with me because she had been doubting our relationship in her head the whole time i barely have anyone to talk to about anything and im constantly under stress because of my major and how difficult it is and the constant examinations and im tired of everything i wish i could just hit a button and become happy or just normal at least.