Hi, I'm not sure if this is in the right category since I can't name my problem.
First I probably should say some things about me. I am a 23 year old guy. I am a student, I love studying languages, I also teach them and love my work. I am a very introverted person. All the signs of introverted people fit me perfectly (I actually only recently realized this and it helped me understand myself a little better).
My problem is hard to describe but it’s something that comes back every now and then (well, actually quite often, the frequency changes) and I think it has to do with a lot of other things/aspects which I want to describe:

Sometimes I just want to isolate myself from the world, not see anybody. This feeling comes very suddenly and I don’t even want to talk to my closest friends (of which as an introvert I don’t have many). It’s like in a second I start feeling like this and I refuse to say even 1 word. I just kind of shut down like a machine and don’t answer anybody with more than a nod and I can’t even bring myself to smile.

I am a person with a huge inner world and I am very emotional in that I long for love and always am in love with somebody. For almost 2 years I have been in love with my male colleague (I am gay) who is straight. Since I am such an emotional person, I have been very sad about this and I always let emotions like this take control over me. I think about him all the time, dream about him, wait to see him, even though I know it’s useless and I will never get what I wish. We actually are friends, but it’s more like a colleague-friend relationship; we aren’t the closest friends. As I said, it’s been two years. I feel like I’m walking in circles. (I know though what I feel for him isn’t true love. I am in love, but …platonically. Maybe just infatuated).

Which has to do with another thing. I have a low self-esteem and I actually don’t know why. I’m not saying I never acknowledge my qualities; I acknowledge my qualities as a teacher or a learner of languages. For example, I actually know I am very talented as far as languages are concerned. But since I was, like, 16, I have been feeling very bad about my appearance and I still call myself ugly and unworthy of love. If a guy even wanted to go on a date with me, or expressed that he liked me, I would be like “why does he like something as worthless as me?”. And as far as “walking in circles” is concerned: I am madly in love with the colleague I mentioned but I don’t even try to forget him, maybe by trying to date and not wait for him to “become gay”. God, I even know he asked one of my female colleagues out on a date (she refused) and not even this has helped me get over him.

Then there are these times when I kind of hate him for being so pretty and beat myself up over being ugly. BUT I know appearance doesn’t matter and what matters is inside. I KNOW THAT. I just never brought myself to really believe it.

I feel like months are flying by and nothing is changing. My feelings for him aren’t changing. My attitude towards myself isn’t changing either. Sometimes I hate myself for being antisocial. Like a few days ago, I had passed an exam and wanted to reward myself somehow. I wanted to go have lunch (by myself) at McDonald’s but passing by I saw a lot of people inside which made me change my mind and I preferred to stay hungry. I feel this fear or something. There’s a feeling of inferiority in me which I cannot get rid of. Even today I walked into our teachers’ room where my colleagues and the one I like were talking and laughing and suddenly this feeling of inferiority came over me and I felt like a loser. Often when we go out for a beer with my colleagues I feel like I am the weird or even sick one just because I don’t talk as much as the others. What makes me even sadder/madder is how I (for example being out with my colleagues) can’t defend myself against those bad feelings and everybody has fun but me. I feel like the stupid one, incapable of having a good time. Then I hate myself for being like this and I often feel rage towards others for being so … happy.

I am not saying I feel like this all the time. But it is often. When it passes, I basically feel like a happy person. But sometimes I feel like there is this weird sadness or pessimism or something inside of me and I have no idea how it got there.
When I was a child I used to get called a ****** and insulted by words about my appearance. Could this perhaps have left something inside of me? Because I have no idea. I don't know what's wrong with me.