I was working a full-time job in the ER when I decided to retake the MCAT. Working 4 shifts a week was brutal when it came to trying to study, so I switched to part time (2 times a week). My test is April 23rd. From when I started studying, I had 145 days to study. Currently, I am doing fine studying and working my part time job but honestly it is a real drag sometimes and can stress you out when you need more time to study. I would say it is very possible to do both since you don't take you test until May. It would be a lot easier if you just focused on the MCAT though (and probably better for you long-run interests).
It should also be noted that I request overnight shifts at an ER where there's a very small population, so I usually get about 5 hours of studying done DURING my work (normally I work smack dab in the middle of a major city in Texas with a 120 room ER. No studying can get done there ha.) Basically, I have a scenario where I can study and work at the same time, so keep that in mind.