Is the saying: "O Allah, bless Muhammad—a blessing by which my worries are relieved and my distress is removed" considered polytheism with Allah, by making the prayer upon the Prophet (peace be upon him) relieve worries along with Allah?

The mentioned formula for sending blessings upon the Prophet, peace and blessings be upon him, is permissible and not shirk (polytheism); because it is a supplication and a means of seeking intercession through a righteous deed, even though it is preferable to adhere to the reported formulas. Sending blessings upon the Prophet, peace and blessings be upon him, is a cause for the alleviation of worries, the forgiveness of sins, the fulfillment of needs, and salvation from the horrors of the Day of Judgment, as stated in the hadith: "Then your worries will be sufficient for you, and your sins will be forgiven." It is among the greatest means for removing worries and sorrows.