All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah and that Muhammad is His slave and Messenger.
We implore Allaah, The Exalted, to facilitate your marriage, to soon bless you with recovery from your illness, and to safeguard you from all evils by His grace; verily, Allaah, The Exalted, is Able to do all things. Hence, you should turn to Him in all your affairs and needs; He says (what means): {Is He (not best) Who responds to the desperate one when he calls upon Him and removes evil and makes you inheritors of the earth? Is there a deity with Allaah? Little do you remember.} [Quran 27:62] He also says (what means): {And your Lord says, "Call upon Me; I will respond to you." Indeed, those who disdain My worship will enter Hell (rendered) contemptible.} [Quran 40:60]
For more benefit, please refer to fataawa 88296 and 92363.
There is no doubt that marriage is one of the best means to extinguish the fire of passion in the heart. It has been reported on the authority of Ibn ʻAbbaas that the Prophet said, "There is nothing like marriage for two who love each other." [Ibn Maajah]
The Muslim is encouraged to hasten to marriage as people’s lives are limited and hindrances may emerge. If you cannot marry this girl because of an impediment, legal or of any other kind, then look for another girl to marry. You should not make it difficult for yourself; you can marry any other girl. You should leave all your affairs to Allaah by depending upon Him only. Hopefully, He would compensate you with a better, more righteous wife; you do not know what is best for you. Allaah, The Exalted, says (what means): {...But perhaps you hate a thing and it is good for you; and perhaps you love a thing and it is bad for you. And Allaah knows, while you know not.} [Quran 2:216]
This girl may also be blessed with a good husband with whom she can find happiness. We believe that the matter is simple, and it is not worth destroying yourself over a perishable, worldly matter. It is strange that you are thinking about committing suicide because of that. Do you realize the evil consequences of suicide? You would incur the gravest misery and greatest loss ever upon yourself (by doing so); please refer to fatwa 22853. You must not think about that at all, let alone commit it.
Allaah knows best.