Are these intrusive thoughts—which include threats of bad things happening if you don't pray a missed prayer after Asr, prolonging prayer after Fajr, and cursing oneself for not going to the mosque—considered obsessive-compulsive disorder (OCD), and must they be followed?

We ask Allah to grant you well-being from this ailment. To be saved from it, turn away completely from these whisperings and pay no attention to them. Instead, dedicate yourself to your obligatory worship. If you have missed prayers, count their number and pray them in a way that does not harm your body or your livelihood. If you have nothing due, then you only need to perform the obligatory prayers. It is permissible to pray missed prayers after Fajr and after Asr, but it is not permissible to perform unrestricted voluntary prayers during these times. Be diligent in praying in the mosque. And beware of supplicating against yourself, for the Prophet (peace be upon him) forbade that, as it is authentically narrated in Sahih Muslim from Jabir (may Allah be pleased with him) that the Prophet (peace be upon him) said: "Do not supplicate against yourselves, and do not supplicate against your children, and do not supplicate against your wealth, lest you coincide with a moment when Allah grants what is asked, and He answers you." And beware of continuing with these whisperings. We advise you to present yourself to a trustworthy doctor in compliance with the Prophet’s command (peace be upon him) to seek medical treatment.