Breakups dating again
If you want to date someone else, you at least need to clear up some brain space so there's room to let someone else in, even if it's for just one date.
Even if you're mentally conjuring up tiny versions of your ex and daydreaming about stepping on them like a giant, that still counts as thinking of them.
Rejection is just a part of dating, and you need to think honestly about how you would feel if someone turned you down or if things didn't work out. If, after a first date, you're going to be completely devistated if this person doesn't want to see you again, you clearly aren't ready to date.
If you know your response to rejection is a depression spiral of self sabbotaging "What's wrong with me?
Healing a broken heart isn't a one stop shop, and that shop isn't another person or relationship.
Properly find happiness on your own before you think about getting into a relationship with anyone else.