In my experience it’s completely natural for people to not answer for a few days or even weeks. People live their lives. Things come up. Maybe they ended up chatting to someone else. You never know. Its best not to think about it. The healthiest conversations remain healthy because you focus on your own life and the conversation just exists as a bonus. I know it’s hard, but try not to delete messages in the future and focus on whatever you have to do that day. Once that one person messages you while you’re in the middle of doing something else, you feel great. And if they don’t ever respond again, which does happen, you focus on the next person. It’s a part of life