Hello and I’m sorry for your pain. I recently went through a breakup (though admittedly not as tough as yours) and I’ve found several books to be helpful. Viktor Frankl’s “Man’s Search for Meaning” is a great tool to find the meaning and positivity in life’s inevitable suffering and Pia Melody’s “Facing Co-dependence”, though this particular one only applies if you are codependent. The only reason I figure you MIGHT be codependent is because of your apparent lack of self esteem (saying you think finding a partner would be like winning the lottery- no it’s not, you deserve a partner and it will happen!). Low self-esteem is one of the five symptoms of co-dependence.
Perhaps you need more time or perhaps you need to continue working on yourself and finding happiness from within. Frankl suggests a technique called paradoxical intention, or trying the opposite of what you want. Take time and focus on yourself and forget efforts at dating and I bet you will find someone eventually.
These are all suggestions and paraphrasing, of course. I wish the best of luck to you.