Although I'm not a 'method actor' in the Strasbergian sense, I am in the Stanislavskian sense, and it always helps me to have a routine to go back to. After a long, intense day of rehearsal or class or whatnot, it always helps me to come home and make a cup of tea and watch an episode of my one of my favorite TV shows. Just to remind my brain and body that I'm not acting any more. Some people do yoga, or whatnot. Whatever you need to do to settle back into 'pedestrian' life. Hope that helps!!
I know exactly what you mean! My "method" for acting is just BECOMING the character. There is NO me when I act, only them. I learn about their life before and after the show, how they feel, why they feel it, to what extent they feel it, how they would feel if some other thing happened, literally every detail about them. So, when it's all over it can be REALLY hard for me to get back in to myself. For me, I like dance it off :p Doing something really active like dancing or working out for some reason helps me get back out of character.