Im depressed, can reddit help me turn around before it takes over me.

I find myself every day getting more and more depressed. A little bit about what causes it. I joined the navy after being dumped by my girlfriend a while back, i considered her the one that got away. I went into a very depressed state until i joined the navy. Once i had joined though i became very happy, i thought i had found what i was meant to do. I lost about 1/3 of my body weight in fat, and was training for a special warfare position, right after i passed the PFT for the job, i was medically discharged for a concussion and severe migraines. This was when it got really bad, my dream was crushed in front of me.

I moved back to my hometown, and am currently living with my parents until the end of this month. I find myself getting more and more lonely and i think this is the main cause of my depression. I have friends, but nobody really talks to me. I hookup with a lot of random girls but i find that every time i do this the aftermath ends in me being more depressed than before. In the last 2 months I have slept with 7 different people but i find that im only happy during the time leading up to the hookup, the hookup itself and afterwards are just depressing. I feel like nobody cares about me more than to just have sex with me, and i find myself wishing someone would care about me just a little bit, just enough to want to talk to me because they want to. However this doesn't happen, and i find myself getting more and more depressed because of this.

What can i do to stop this, I just want someone to care about me for once. does anyone have any advice on what i can do to turn around this depression?

TL:DR Im depressed, joined the navy, was discharged for concussion/ severe migrains, so lonely it hurts, random hookups make me feel even worse, just want someone to care about me....help me please.