To be frank, I think you have little to no self-worth. I just broke up with my bf in January and I was down and out for about a week or two. And while I still think about him every day and cry from time to time, I refused to have it completely overcome me.
I know different people cope in different ways, and I think you are allowed to feel the way that you feel… with one exception – in this process of grief, continue to love yourself.

If your worth is solely based on how others value you… than you will constantly be in the position that you are in now.

What do you like about yourself? What do you enjoy doing? What hobbies can you enjoy?

Love is a beautiful thing, and as cliché as this is going to be, you cannot love anyone unless you love yourself. I don’t think you love yourself very much, which is a shame because I am sure you are an amazing person with a lot of love to share.

I would recommend a few things:
1. Grief… let it out.
2. Stop contacting her. After my break up I continued to be “friends” with my ex until I realized that talking to him only caused me more pain and left me feeling confused. It is not until I completely cut him off is when I truly began to move on from the relationship.
3. Love yourself. Better yourself.

I think resigning from your job only added to your self-pity. Just because one thing went wrong in our life doesn’t mean everything else should be neglected. I hope you can find another job soon because I believe this could help you with your self-confidence.

Lastly, I will end with this statement that my aunt told me a while ago… “Build your own happiness. So even if your lover leaves you, you will always have that happiness that you built for yourself. No one can take that away”. Your beak up was only brutal because you are making it brutal. You care causing a lot of your own mental anguish within yourself.

Good luck my friend.