Hey, Joe. Yeah, i and probably alot of the rest here have had about that feeling as well. I had that feeling, though, when i was already terribly depressed and lonely, and what triggered these thoughts were simply that, because i was so sensitive as a human being and inactive when i was alone because of my depression, i didn't do enough to be of any value to anyone; my definition of a "good" and "valuable" person is someone who actively does something to improve people's (and animal's) lives. I were always longing for love and closeness to someone else but that never seemed to come. That's why i felt so small compared to everyone else around me; somehow, being the proud, important looking and sometimes (compared to me) careless people they were, they managed to find a partner, buy a home and a car, and even get kids together. It was just as plain goodnes and being kind and helpful didn't mean honeysuckle to become happy in life. While i were trying to be the best a human can be, i still hadn't find the only thing i was asking for in return; some got **** love (that includes from my family and friends). No wonder i felt useless and below every, single other human being; i apparently didn't do my job good enough since the man upstairs (which was who i blamed for most of my days, back then) obviously didn't like me very much.
This was my reason, my curse for having just as low self-esteem and sense of uselessness as You have today. I saw myself as a robot who's only purpose was to devote it's life to make good for others, since i didn't seem to mean anything anyway. The problem was that, since i kept a mask on that i was fine myself because i always thought that being sad around someone would make them sad and in turn shorten their lives for a few minutes, i were actually hiding that i was i need of some attention. I were one heck of a liar!
I were way too much concerned with everyone else and how they looked and blablabla. You know what i have learned? If You are a good person and actively do good for others but don't get anything in return, they don't need You. They might apprecciate it, but it's not that they wouldn't manage to go on with their lives without You. That's why i, nowadays, quickly learn when it's time to leave someone alone and accept a good farewell. Another thing i've come to understand, rather late in my life compared to others, i guess, is that once You've done enough for someone who truly does need Your help, most of them will run away from all that remembered them of the old days.
My answer, was getting something that i wanted. When i finally did find love i found the support i needed to do whatever i wanted to in life. A relationship of love is what made it all possible for me. If You want to give alot of love You must get alot of love, and the little amount You'll ever recieve from helping people is way too little. Of course everyone aren't as crazy as i am, but love is probably the most positive hit someone's self-esteem could ever recieve.
Once You've found love You've found the ability to start looking for or realize Your dreams. I'd like to say this to You:
You think You're pathetic - What are You trying to reach? You've heared people positively comment Your work and still don't think You're good? How far do You have to go to feel that You are doing the best You can?
You feel ugly when You're near others - How do You actually look? I know so many with a low self-esteem who are really handsome and who simply haven't found a good hairstyle or clothing style to better fit them. We're all different and can't always look as good as someone else just because he or she looks good in something. It's all in the eyes of the beholder, and what kind of prejudices don't You have agains't Yourself?
You're not as outgoing as "everyone else are" - What does "outgoing" mean to You? What do You want to be able to say to a person You never met before? Do You think that, just because that dude over there asked that dudette what the time is, he's outgoing? If You feel as someone less than what You really could be, and ugly, it is no wonder You aren't "normally" social.
Just how are You doing, Joe? Are You happy with Your life, apart from being who You are? Do You think life has treated You well enough for how well You've treated others, so far?
I don't want to go to conclusions just yet; i personally know several people who are just like You (and even salesmen as well) but they all seem so terribly unwilling to quit striving for being the best they can be that they are really hard on themselves. They can't accept that they didn't manage to perform as well as they thought they'd would in several chapters of their lives. We're all good at something, but very few of us are good at alot. Maybe You simply haven't find Your niche just yet? The strongest ant don't always have to find and carry the heaviest stick back home, until he starts looking around the right bush.
PM me if You want to keep things private, and if anything seems relative to Your life, of course. You'll find alot of great people here, and soon enough i think You'll find someone who will be able to change Your self-esteem beyond Your imagination. Welcome to the forum.