I've got a poster of 7* next to my bed, and one of rub on the other side. Any time I'm feeling lazy and roll away from the 7* poster in the morning I'm greeted by rub's lazy fat ass. That quickly motivates me to get out of bed and train like 7*.
Seriously, two things. (a) routine. Get in it and stay in it. (b) don't make yourself feel like crap in the first place. Eat well, get plenty of sleep and look after yourself.
OTOH I've found some people just have the motivation to train by themselves and some don't. The ones that do are in the minority of the general populace. It's easy for them to stay sharp. The others train sometimes but never really make a habit of it. I hope for your sake you're in the minority group.
"If trolling is an art then I am your yoda.if spelling counts, go elsewhere.........." - BL
"I don't do much cardio." - Ironfist
"Grip training is everything. I say this with CoC in hand." - abobo