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I have been working for my current company for 5 months. I work as a software developer, I also fix some bugs on the company's web if I'm asked it.
I've studied IT, but nothing developing related: I did a network degree, but we studied Java very briefly in one of our "free" subjects and our teacher sent the best of us to programming companies for the internship (since developers are very demanded in my city at the moment).
I did my 3 months of internship there and they extended my contract for a year. It was a little company (I was alone at first, we were 5 at the end of my contract) and they started dropping us for money reasons. That was 2 years ago.
Then 5 months ago my mother told me that one of her friend's spouse is the boss of a good company here. I went to talk with them (it wasn't a proper interview at all) they asked two minor things about me (what did I studied and what technologies I know) and even with my non-related studies they said that they will try, and I started working there.
Lately I've been asigned some bigger tasks and I'm having trouble fullfiling them. I don't like asking too much (but I do if it's necessary and I'm stuck for too long), and I can't stop feeling that I don't know how to do anything. Even the minor problem I encounter when trying to resolve a bug makes me think that I'm here because they overestimated me and they'll drop me if I take one day more doing something.
They had say me more than once "you're fast!", "you're pretty clever" or "you explain yourself very well", but when they asign me a new work I start to think that I'm useless and I can't do it again.
I suppose I'm not the only one feeling this (I'm 24 years old, and in my culture it's not so common to be employed that young and fresh graduated) and I don't know what to do anymore.
How can I stop feeling useless and evade that kind of thoughts in the workplace?
Also sorry if my English is messed up.