I am in a similar boat. I started studying in January and I am registered for April and June. I also work in the legal field and find it impossible to study after work. So, I aim for 30-45 min each morning before work, one PT on the weekend, and one day of rest. It isn't always perfect but, at least for me, consistency has been more important than duration. The guilt you feel is real, though. I experience it too.

Sidenote, I have a mentor who's moto for the LSAT is to make the most of what you've got. I don't want this test to consume my life, so I am going for the most improvement based on my diagnostic score instead of trying to claw at the T14 averages. That's just me, though. I know everyone has their own priorities. Best of luck to you, be strong, it won't last forever.