Just got my braces off

I just got my braces off and they gave me a clear top and bottom (they look like Invisalign) retainers and since my gums are swollen it ha begun to tear my gums pushing past them when putting them on after eating. How can I make the swelling go down? I tried swishing warm salt water this morning and it didn’t really do anything. Also I woke up and my teeth were hurting really badly. I think I might be clenching my teeth in my sleep. (I got the braces off yesterday morning) how can I stop clenching my teeth or what can I do to alleviate the pain after I wake up?