I work full-time in a demanding job so I feel your pain. I try to get up super early so I can work out, feed the animals, and get ready and get to work at least an hour before work starts and study/drill then. I also try to use my weekends (i.e., days off) wisely and do any preptests/blind review then. I also try to find live classes that fit within my schedule (even if it means taking a lunch break at my desk to attend a class) as much as possible, but that is harder, given my sleep schedule. I've found that I sometimes have to take days off when I feel I should be studying/drilling just due to exhaustion and usually when I pick it back up again (sometimes a week later), I am sharper because of the rest. You really have to listen to your body and try to find a balance - good luck!