What is the interpretation of unanswered prayers despite persistent supplication and taking all necessary measures, and the questioner's fear of despairing of God's mercy, and is her sin that she has not saved anything for her Hereafter?

It is recommended to be patient and seek reward from Allah Almighty regarding His decree, for Allah is more merciful to His servant and always decrees what is good for him, though the wisdom behind His actions may be hidden. This trial may bring reward for the patient, as stated in the noble verse: "Indeed, the patient will be given their reward without account." (Surat Az-Zumar, 39:10). Among the wisdoms is also striving in supplication, for it is one of the most beneficial weapons of the believer, bringing the servant closer to his Lord and achieving what he desires, or warding off evil from him, or saving its reward for him until the Day of Resurrection. One should also take measures to lose weight, be optimistic, strive in studies and life, and not let this problem be an obstacle to success.