Going through hell , should I text back?

So I started no contact the day after I sent my heartfelt “goodbye” message to my ex over email. In the email I poured my heart out and explained that while I want to be in a relationship, I respect his decision and won’t keep pushing anything. I said I can’t be friends with him because I can’t heal that way. I also told him I would prefer if he doesn’t respond to the email because it would hurt too much. Two days after that email, he sent me this text “I got your email. I appreciate that you explained how you felt. Definitely a lot to unpack. Hope you had a good birthday.”

I didn’t respond and I’m now on day 11 of no contact. I’m hurting every single day and I miss this man so much. He was the only man I ever dated who I could see being my husband. I’m so shattered and idk what to do. Since then I’ve gotten a random “hello” text from a random number and another random call from an unknown person. Idk if it’s him, I could just be going crazy. I’m trying to maintain no contact but it’s hard because my heart wants him so much. What should I do?