Here is how I see things. Our personalities, the perception other people have about us, our own perception of our own self, our actual attainments, the degree to which we depend on these things are all very dynamic. You may be a loser now but you may have been great in a previous life and might be in the future. A successful and a well respected man/woman now, may end up being a loser in the next life and sometimes even in this very life itself. Legend has it that Buddha in a prev. life when he was a merchant killed his own brother for money; and also in another life as an advisor to a king committed adultery with the queen. Also there is the famous story of a serial killer who got ordained and became very successful. Is your situation as bad as this? Even if it is, there is always the possibility of change. We all have been losers and we all have been successful - nothing is set in stone.
To feel good about onself - engage in voluntary work. Hospices are great place to start.
To minimise bad things from happening - commit oneself to the 5 precepts and observe them without fail.
To increase the likelihood of good things coming your way - be generous; donate your time, service, money etc.
If you have done bad things to other people - go and ask for forgiveness from them and try to rectify the situation as much as possible.
I wish you all the best!