What's wrong with me?

Hi, I guess I’m just posting this hoping someone might recognise these symptoms or even have experienced similar problems themselves. I’ve always had poor self-esteem; considering myself unattractive and fat, with a dull, selfish personality, weird interests, and never quite clever enough. I’ve been bullied and insulted by others and repeatedly let down by so-called friends and consequently I struggle to see the good in others intentions towards me. I tend to dwell on the past and worry about almost everything and feel inadequate around others. I went to university last year, lost my close school friends in the process, lost loads of weight, and became even more of a workaholic. I am so miserable there always panicking about my studies and feeling so alone, but at the same time reluctant to socialise with others. I can’t work myself out. I’ve even fantasied about death, and despite the fact I am underweight I am terrified of putting any weight on. I am obsessed with food and preoccupied with what I eat during a day. I do eat of course (my parents ensure that and I hate to upset them) but I swear I’m getting fat again although I am told I look no different. Anyway now I’m back home and summer has started. I should be happy, right? But the melancholy seems to return sometimes even now. I follow these set routines each day and I can’t break them without feeling anxiety, I am so easily stressed and angered, and a lot of the time I just want to be alone and for things to be silent I am that irritable and impatient. I hate this as I know it makes me an unlikeable, even more unattractive person. I wish I could work out what the hell is going on in my head and fix it. This was not what I wanted out of life. I am filled with regret and nostalgia…it’s so pathetic the only real joys in my life now are food and my daydreams. I just don't know what to do...