What is the way to get rid of obsessive thoughts related to the personality of Prophet Muhammad (peace be upon him), specifically concerning the hadiths that show the virtue of praying upon him, and how can one convince oneself that these hadiths do not mean that he "loved to praise himself"?

The cure for waswasah (whisperings/obsessive thoughts) is to ignore it and not pay attention to it, because it comes from Satan who wishes to divert the servant from what benefits him. You have erred by allowing Satan to have power over yourself. It is not permissible for a Muslim who is not armed with religious knowledge to enter websites of those who are astray. A Muslim must seek religious knowledge. Your eagerness to convince yourself, your continuous seeking of forgiveness, and your fear of disbelief are evidence that what you are complaining about is waswasah and not a doubt that takes one out of the fold of Islam. The Prophet, peace and blessings be upon him, was the master of the humble, and he spoke of his virtues to convey revelation and to inform of Allah's blessings so that the Ummah may benefit.