What is the precise diagnosis of my condition and its treatment in light of the symptoms I have mentioned, and what is the ruling on subscribing to a matchmaking service and getting to know someone with the intention of marriage?

Allah alone is the Healer, so turn to Him and cling to Him. Remember that your patience in the face of tribulation has a great reward. You must persevere in remembrance (dhikr), obedience, and reciting the Quran, and trust in Allah that He will provide you with relief and a way out. Remember that this world is fleeting, and the Hereafter is the eternal abode, so beware of the whispers of Satan. Occupy your time with what benefits you in this world and the Hereafter.