Hi, I recently fell 2 times after 90 days clean, a week apart from each other. Part of the reason, especially that second time, is that I've lost my why - the fire inside of me that is really pushing me and making me want to reach this goal. Like, I've reached 105 days and 90 days before, I know I can control myself and don't need p&m if I don't want them.
Another part of this is that, weird-to-say, I've noticed my body, and I like it. It's a pretty nice body if you will. But as a bochur I don't really have a constructive way to use these/all of my faculties. 
Further, another factor is that I feel as if my yirah is lacking. I don't quite know how to explain it, but it's hard for me to really understand and internalize how each of my sins directly affect my relationship to Hashem. I am in the process of learning a maamar on the subject with my rabbi and I think it will help to bear fruits.
Any and all words of inspiration would be extremely helpful. I want to really try to internalize and understand this goal for the place I am at in life. (Also for reference right now I live mostly on my own - I have a roommate, but we have our own rooms - and I attend university. However I graduate soon and with BzH be attending yeshiva afterward. I feel like attending yeshiva will help me to redirect my energies/focus and I will be able to control myself even better because I will have people around me 24/7 to keep me accountable.)

Try reading a chapter of The Battle of the Generation every night. It will help you keep your motivation up. The link is below in my signature. 

Hey, that's amazing that you'll be going to Yeshiva! 
Every sin has two components. One is that if we do it then we have not listened, and the other is the deep spiritual power that lies within that act, the inherent effect of that act. When we don't listen to Hashem, we have distanced ourselves from Hashem. It is not a punishment, it is a natural reaction of the path we have chosen. Much of the way these things work is way above my paygrade, but we know from Hashem's Torah that that's the way it is. And we know that the name of this game called life is to gain closeness to Him. So G-d help me! And you! And all of us:)
Hatzlacha!