Carseat drama

My son is impossible to get in carseat. We have both an infant one and I just installed a convertible one in my car. Picking him up from day care took five minutes just getting him in the seat. This has been going on for at least a month. We used to be able to distract him with peek a boo or songs. A bottle worked for a couple of days. Now nothing works. It's not just from daycare, it's to daycare, the grocery store, his grandparents, from the park. Anywhere. He does these back bends and whines. It's impossible to even get the straps around his shoulders and when we do sometimes he twists and I worry he's going to strangle himself. Eventually I'm able to hold him down to get him properly strapped in and he is downright wailing like I'm hurting him. Idk what to do. I was literally afraid I wouldn't be able to leave daycare because I couldn't get him in the seat. Help!