Hey hey if this is true (sorry if that offends you, it's just there are some jerks out there that like to prank around..) I'm sorry
For a start, do you spend a lot of time alone stuck inside? First I'd stop that, and don't just think "I'll do it" and never get round to, start right now! Go outside and take long walks, around streets, up hills, anywhere. You might not like it and want to go back home and lie around again but you have to put that thought away, laying around won't get you anywhere. Feeling good about yourself does sound hard to do, but it's a starting point. Get some good exercise at first , don't cost money, and it's cheaper than wasting electricity watching T.V and the computer! XD
I'd really start with that though, and maybe a gym membership? I don't know the costs, this is coming from a girl who is too young to go to gym, but you could ask your sister for help. It might sound embarrassing but it wouldn't cost a lot, and I'm sure she would help as you are feeling so down, what sister would go "Whatever i don't care about you" when they are grown up and mature and happy by the sounds of it that they are going to be married soon?
Start with that, or even swimming if you know how? Start with exercise, I know this sounds stupid, but it makes you feel good, and you'll get confidence in a way as a starting point
You say you work full time? Oh darn, do you have free time at weekends to do this?
Your job.. well what do you want to do in life? You might be thinking "I don't know, I just want a good living.." if that's the case go on job websites and look at all the categories to get inspired, they show pay too, but iof course you aren't going to be accepted straight away. Find something there that you like, a career that sounds not bad to you, please don't choose a career you hate for the money, but a good one that won't get you depressed working full time and the pay doesn't seem to be lousy. Like say someone wanted to be a park ranger, but the prices were lousy, I would say 'don't bother' and choose something else they like that will keep them stable
I've wrotten quite a bit.. I hope it isn't completely useless.. Oh and why not chat rooms? That sounds pretty lame, but you don't need to tell people about you, but don't lie either, but just talk as I read you talk to yourself everyday.. you should never do that, that's so horrible for you, find a chatroom and force yourself to talk, anything, talk more and more and you will get a bit better
And forums are good for talking to, you don't need to talk directly, but discussions and arguements about topics could be okay, alright I know this is a sort of forum but it doesn't allow much communication, try a popular forum with posts, and discuss anything just as long as you are making communication, continuing in this isolation isn't going to get you any better.
good luck and try not to think badly about yourself, infact if you focus your thoughts around your self when there isn't much positive, is not a good idea, get thinking of future goals and stuff =)
(oops so long sorry!)