My 3yr old son will be spending the weekend with his dad and I’m freaking out

Me and my sons dad ended things on good terms and we do live about 3 hours away from each other at the moment. My sons dad will either visit here or we go to visit him and thats how we agreed to do things for now. BUT he is currently on his way here and he will be taking our son to spend 3 days with him and I’m freaking out a little. I know I shouldn’t be because he has all the right as his parent but I’m not use to being without my son 🥺 can someone please tell me how I can calm my nerves down? The closer his dad is getting the worst I’m feeling 😬 anyone that has been in this situation has probably felt the same way and I need advice for you. It’s our first time being separated from each other in about 2 years so I know my son will eventually miss me but I also know that he will be happy to be next to his dad because he hasn’t seen him in about 4 months.