Oh Targus, i'm so sorry that you are having such a struggle right now. If it helps, I am also feeling in a dark place right now and that as alone as you are feeling, you have support, even just through an internet forum like this.
I see you have been struggling in general for some time. I want you to know that however bad things feel right now, you WILL overcome them. Today is today and tomorrow is tomorrow, its all about taking one day at a time. Allow yourself to feel sorrow and all those things you need to get out of your system. Relationship breakup's are just awful, I know, it feels like the whole world is going to end. You have to remember that life still goes on, as hard as that is to swallow, you will also learn from this experience. Things happen for a reason, maybe she just wasn't the right girl and in time you when you start to feel a bit normal again, you will be able to take a step back and see what went wrong and why. For the time being though, maybe the best thing would be to live as a single individual, to become more self reliant, it can be a tremendously valuable thing once you start to appreciate yourself as a person and all the individual qualities you possess as a person. You are well loved here, I know.
In the meantime, if you ever feel really low, you can pm me, there is also these really helpful people you can email(jo @Sam aritans.org) who I have turned to a few times in my own life crisis's. It might also be a good idea to get yourself on a waiting list to see a therapist, you can even request to be placed on a CBT list which is a short, intensive course of therapy which might help you get out of some of those destuctive thought patterns. I hope some of the advice here and from others is a little comforting and helpful. Be safe. (((Hugs)))