Developing your relationships starts with you. You cannot know where you are going or really assess what is happening on the other side of the feedback loop without knowing yourself. This involves some work--sometimes intense work--to manage your emotions or thoughts or behaviors.
Chicken Soup for the Soul developer, Jack Canfield, has a concept which sums up this process: any given event plus your response equals the outcome. In that equation, most people will focus either exclusively on the event (a trauma, a perceived slight, act of God) or exclusively on the outcome (feelings of hurt, loss of resources). This focus is not only a recipe for helplessness and a decrease in self esteem, it also gives power to ALL the parts of the equation that we do not have control over. We only have the power to change our reactions.
Now, this is 100% easier said than done, but it is also true that no one else can do the work to change our reactions. If we react with hopelessness and focus on all the things that are happening wrong around us, then we continue to stay powerless. You can see that if that happens regularly, or even semi-regularly, your perception of what you are capable of being and doing can become negative and so can your self esteem and self image. Soon, negatively approaching each new day becomes a self fulfilling prophecy.
So, where do you start? First is becoming aware of what you have control over each minute--your emotions, your thoughts and your behaviors. Is complaining to your colleague a stress reliever or does it keep you verbally and mentally stuck? Did having that second (or third) drink help you to forget or did it just push the problem off until the next morning?
Second is developing the self awareness to know which strategies to use instead of the ones you've identified that no longer work. Maybe you remember that running is an excellent destresser and brings you clarity. Or you know that watching a certain comedian will leave you in stitches and more able to cope. Maybe talking a walk at lunch (by yourself if you cannot stop the vent from becoming a complaint) will keep your energy up for the rest of the day. If you don't know, it's time to explore--and remember not to settle for good enough for these strategies.
Finally, use the strategies. Simple, but not really because unless these strategies are consistent and a habit, then it will be easy to fall back to the strategies which created the low self esteem.
Remember, you are fighting a negative frame of mind and it is very powerful. You can fight it though, and you will believe it too once you are in a more positive frame of mind. Until then, hang in there and call me if you need some session time.