Hey
Huston I totally sympathize with you. I asked out a girl three years ago and she turned me down cold and I spiraled. I was the most severely depressed I've ever been and decided to do something about it. So I gave myself a goal and said that I would change everything about myself and that in a year's time, I would have a girlfriend.
SO I started getting a haircut every 2 weeks ($15-20 per cut), going to the gym at 5 in the morning, buying a bunch of new clothes, and trying to be more outgoing and friendly with everyone. And you know what changed about me personally? Nothing. That year went by and I didn't even have a girl I was interested in. I was still the same miserable guy I was, except now I was sleep deprived from waking up so early and broke and still single. Changing what was on the outside didn't give me the answer to my problems, and I don't think it will give you the answer either.
That being said, I always encourage my friends to exercise and lift weights (I do bodyweight exercises due to injuries, but do what you can handle). It's good for your health and research has shown that it helps you make healthier choices. I also encourage good hygiene, since you ideally want to share your personal space with someone. In terms of looks, you have the face and body that you have, so all you can do is make the most of it. No guarantees in that department, but you owe it to yourself to try to polish it up.
As for the personality bit, that was the hardest lesson I learned that year. I had been faking it so hard and trying to be this positive upbeat guy who was friends with everyone and liked going out and being social. But that wasn't who I was, and every time I tried to be that person I hurt myself inside. I'm not gonna tell you to "just be yourself". If that was all that needed to happen, you'd already be boo'd up. I will say that you should learn to love the things about yourself that make you who you are, both the good and the bad. I can be quite blunt and sarcastic, but I'm also observant and loyal. I accept that as who I am and I know that's what I bring to the table. Confronting the truth in your personality and being at peace with your strengths and weaknesses can be very ratifying for your self-esteem. And I can tell you, the more comfortable you are in your own skin, the more confident you'll be around others. When you're not trying to hide who you are, you can spend more time getting to know people and making meaningful connections.
Lastly, I'll tell you what a friend told me: "No one is laying awake at night thinking about you." No matter how stupid you think you look or act, chances are, nobody cares :)
P.S. PM me if you want to talk more