Mrs Conceited

I have never in my life met anybody as conceited as I am. It sucks, and I don't know how to change it.
It has nothing to do with my appearance, in fact, I believe I'm a very average looking person, HOWEVER I always assume that certain situations are about me. Me, me, me...
For example, someone (even someone I haven't actually seen or spoken to for months) will post a random comment on facebook and I will automatically assume the post has something to do with me and that the person is subtly trying to send me a message. Especially if it is something bad. I always assume people think the worst of me and as mentioned in my previous post, are conspiring against me.
I believe that people close to me has heard rumors, and instead of asking me about it, they just believe the rumors and try to "get back at me". Aarrgg.. frustration is not the word.
I try my best to be nice to everyone I meet and talk to. Because of that, I think that people might think I am too nice, and then they don't trust me without realizing that there's nothing more to it than me just wanting everybody to be happy.. it's quite sad, actually.
Today at work, one of my colleagues were talking to a lady (I didn't know at that stage that it was her mother), and telling her something like " apparently the guy treated her like shit" and they were laughing etc. and I thought they were talking about me, because my previous boss treated me and my ex-colleagues badly, and that they don't believe me and are trying to scheme behind my back. It's crazy. I don't even think this specific colleague even knows about my previous job situation...
I try my best to always be honest, yet I still believe that people think I am a liar.
I try my best to be loyal, yet I still believe that people think I am a snake.
I try my best to be friendly, yet I still believe that people think I am fake...
You get the message?

Anyway, to end off, count the number of I's and me's in this post, and you will see what I mean...

An Introduction to my Paranoid mind.

I can count the number of times I've been paranoid about something bad happening and it actually ends up happening, on my one hand. Compare that to the hundreds, if not thousands of times I've been paranoid about stuff I end up laughing about later, and you have a definite winner.
Just to give you an idea,here is one thing I am currently paranoid about:
I worry that the people that I work with actually can't stand me because they've heard some elaborate rumour which is completely untrue about me, and instead of confronting me directly about it, there is a major plot going on to try and get me out of the company. Part of their plan is to keep me under surveillance from one of the apartments opposite mine and other such ridiculous thoughts.
I know for a fact that some people might think I should consider getting psychiatric help, and I can assure you that, had I had the means, I would have definitely seeked professional help. However, I don't have the means, but at least I have recognized my problem and I can work on it on my own  - thank GOODNESS for the wonderful Internet and green pastures!
What frustrates me the most, is the fact that I KNOW my thoughts are irrational, yet I can't do anything to stop them from happening. I can only calm myself to a rational state.
I love my job and colleagues so much, it's an absolute shame that I'd waste so much time by obsessing with my demons...