From your description above I understand that you are having hard time. It looks like you are having depressive symptoms. These distraction reduced concentration skipping classes and loss of interest may be part of your depression also. Detailed evaluation has to be done.
Smoking or alcohol intake also might be a part of your underlying problem which are worsening the problem.
Masturbatory practises need some more elaboration regarding frequency, time spent, control etc.
Suspiciousness towards your partner on what context needs elaboration.
Unwilling to do b tech is the result of your underlying illness.
So you will have to consult the treating psychiatrist and discuss in detail.
For time being continue the meds and consult again at the earliest.
Next Steps
consult at the earliest. Discuss openly about all the issues with psychiatrist. psychotherapy sessions also would help. Take your meds regularly.
Health Tips
relaxation exercises like drop breathing..yoga
regular physical exercise
being regular with your follow ups