I'm a closeted agnostic and it's making me miserable and worsening emotional problems. do you have any advice?

Talk to a counselor: You should feel comfortable w/ your beliefs and not feel pressured or stressed to conform to the beliefs of those around u who try to influence u one way or another. Study the different religions ; decide for yourself what you believe. It may help to talk to a non-judgmental friend, counselor or spiritual leader like a priest, pastor or rabbi.

Not a health problem..: …until it affects your health. WHY are you closeted? Your own guilt at rejecting a religious upbringing or fear of rejection by others? Self-acceptance – perhaps with professional help – will help alleviate both. Hard to imagine here in the West, but there are actually nontheistic religions e.g. Buddhism; learning more about them may help you feel more comfortable with your own beliefs.