What is incumbent upon one who has abandoned prayer for several days (six or seven) due to obsessive doubt and hesitation?

You have committed a grave error by abandoning prayer, an act more sinful than adultery, theft, drinking alcohol, and taking a life. You must make up all missed prayers. It is more prudent to make up the number of prayers that ensures you are certain of absolving your responsibility. If you doubt the number of days, then make up the larger number.