Does a Muslim suffer from obsessive whispering regarding ablution, the intention for prayer, and fasting?

The cure for obsessive whispers (waswas) is to disregard them and pay them no attention. If you intend to do something, do not vocalize the intention, for its place is in the heart. Do not interrupt your act of worship, no matter how much Satan whispers to you that you have not made an intention.

When you perform ablution (wudu'), bring to your heart the intention of removing impurity (hadath) or that you are performing ablution for prayer. Do not interrupt your ablution, no matter how much Satan whispers to you that your intention is incorrect.

When you want to pray, intend in your heart the prayer you are performing, and do not pay attention to the whispers. Do not interrupt the prayer or repeat it, no matter how much Satan whispers to you.

Similarly, with fasting, intend to fast, then pay no attention to the whisper, no matter what Satan casts into your heart that your fast is incorrect. Do not make up any of the days you fast merely because of obsessive whispers, and seek assistance from Allah the Almighty.