Feeling anxious

I always feel anxious because I talk with someone I mean he doesn’t respond to my messages but he respond to them late. I get crazy and I really wanna go on fight with this person so actually I have been in this relationship or More accurately situation because he never committed Six years ago I was with him and then after three years I decided to broke up because I couldn’t handle him anymore after three years he came back apologizing and asking me to come to talk to him again so it’s been a month that we’re talking and in this last week, the same feelings are coming back as before three years and I’m starting to get anxious, depressed and stressed all the time because of Waiting for his text, I told him that I broke up again because I can’t handle you said please no don’t do it. I have things to tell you, but I am losing my patience and I cannot control my anxiety please I really want to help.