No, honestly your thoughts are not normal or healthy. Feeling some nervousness before a date is normal.

Normal thoughts are "does my hair look good, will they like my outfit, I hope I don't talk too much, etc."

Your thoughts are "this person probably isn't going to like me and I'm going to be let down like the past".

Normal people have some trepidation on what is to come, but they still go on a date.

You have these intrusive/harmful thoughts that are indicative of something deeper seeded that you might want to figure out or talk to a therapist about. It's not just mere thoughts. It's also affected your actions which is really extreme.

You've provided no indication that this person was anything less than friendly/respectful. To delete someone's number entirely is a very strong reaction to... really nothing at all. Unless he was texting you dick and butthole pics or saying disgusting things, I don't see why you would delete the text thread either.