Well I guess that's another thing that I need to fix.
And don't take stress about it. It's a process, and there is no hurry. And as your relationship has just ended, emotion are a rollercoaster, and some days doing anything may feel impossible. But improving your self-esteem slowly helps you do all the other things, it gives you strength, it makes it easier to cope with feelings and teaches you how to deal with them.
The low self-esteem and self-appreciation makes you easilly feel like worthless, useless, hopeless etc. when bad emotion comes. Wollowing in them and rolling in guilt and shame, feeling like there is nothing good a head for you, cause you feel like you can't have it because of what you are. Then comes envy of others happiness, then bitterness, and that cycle will continue.
Improving your self-esteem actually helps you to be more you, appreciate yourself more, value yourself more, and gives gourage and joy to do and find those things you really want. Give yourself comfort like a good friend would or a loving mother, don't be too hard on yourself. Break-up is always time for learning about self, about the other, and about relationships and life in general.
Last time I broke up, I was devastated. The saddness and depression lasted for half a year, and all I did was either angry, sad, depressed, or when I thought I was happy, I just pushed all the feelings a side and went cold. And now of course I feel sad about my recent break-up, but I can cope with the saddness, deal with it, and I can still see all the good, and appreciate myself. It doesn't crush me anymore, and I can also be logigal about feelings, find the thought befind them, and accept them and let them go. I can feel sadness, but still be quite happy. And above all, my heart is full of hope for the future. It didn't work for us, but next time I'm more me than ever, and there is so many good qualities and happiness in me to love, and I can give love more too.
And you are very young and it's a though lesson, but so rewarding if you are willing to learn. If I just could have learned these things when I was younger... but dealing with useless regret, letting go of the useless burden is the key when lookinng in to the future with hopefullnes.