Dear Kamalnath,
You have not disclosed whether you are required to work from home during the lock down period. If it is so, being a fresher on probation or a probationer on an altogether new job position, you may get depressed in the home atmosphere for want of then and there guidance from your senior colleagues as every novice's mind is a hot bed of flimsy work-related doubts. Otherwise, the reason for your depression must be something else like you don't like the present job or the company which tempts you to put down the papers during the ongoing phase of lock down for the sake of easy and quick acceptance.
Depression is associated with mood swings or mood disorders. It is a kind of feeling down or being hopeless even on flimsy grounds. You should remember that feeling down at times is a normal part of everyone's life. You should try to analyze what makes you depressed - whether the current job or the likelihood of non-acceptance of your resignation. Are you sure that just your exit from the present job would make you feel elated even in the absence of an alternative job? Who knows, your employer may or may not accept your resignation during lock down.
Nobody can give you better advice than yourself. Try to be composed for some time and then decide whether to resign or not.