Hi Nightowl,
I have posted this idea before, but here it is again:
My best suggestion for you is to try to do a little every day. It IS overwhelming to think about reviewing all of those subjects, but you don't have to do it all at once. Starting tomorrow, just study for 30 minutes: 15 minutes in the morning right after you wake up, and 15 minutes in the evening right before you go to bed. Make the commitment to study every day at a certain time or times and do it, no matter how much you think you can't spare the time. Don't let yourself quit until the 15 minutes are up. Even if that's all of the studying that you manage to get in, you'll feel less guilty and stressed because at least you'll have done *something* toward preparing.
Also, try not to get stressed over the amount of time between now and April. You still do have plenty of time to get prepared for the MCAT, but you can't drop the ball now. Best of luck to you.