Steliana,
You're honesty and willingness to admit where you're at is a great start!
Secondly, it certainly isn't easy to change your mindset when you've thought and behaved in a particular and self-defeating way most of your life. It takes much work and personal effort but it's worth it. You can get some ideas from this article I wrote
Develop A Healthy Self-Concept.
Again, it takes effort in the form of reflection, self-analysis and a willingness to change your thinking.
Cheers!