MArtial arts exerise routine??

i have a black belt in Gojuro Karate but i havnt been in karate for about 3 years. I havnt practiced for about 2 months and have become slower, weaker, and more tiring than i ever was before. WHat would be a good MMA rotuine i can do by myself that will get me faster, stronger, give me more endurance and give me more confidence in all? i know karate, some judo, some ju juitsu, tae kwon do, muay thai, boxing and kickboxing.