Be optimistic.Even heaven has a rainy day

Remember "past is past".Theres nothing you can do to change what has happened but you have a present that rely on your work and a future which depends on your present acts.

make sure to stop getting tensed.don't override your problems to cause you depression

Apologize if you have made a mistake.a simple apology wont change anything in you.

If you cant smile at someone at least don't make faces to make yourself look bad.

Be confident in what you do. Your the best teacher to judge where you stand.

And most important Thank God for what you are? always remember where you come from and what is the purpose of being here.
surely things will work out