Interracial marriages do work for Muslims if we live our life according to the sunnah, we have this huge factor in common with all Muslims so i dont see why it would not work. also you are limiting your options somewhat with the whole tribe thing, if your parents do not have a problem with you looking for someone outside of your tribe or race i would really give that a shot, your main criteria should be piety also always ask Allah for guidance and do istikhara and then whatever happens know that it was for the best for you, If you prayed isitkhara for all the potentials that have passed then have faith in Allah and know that Allah turned you away from them because it would have been something which was not good for you make good use of your time whilst you are single, you have a lot of free time for ibadah and also you have time to gain knowledge on your deen, when you get married inshaAllah and have children you won't get much time for these things, it will also serve as a distraction from depressive thoughts inshaAllah May Allah azza wa jal grant you a pious husband...Aameen