hi martina,
i am wondering if you have had a full physical recently? i'm not sure what PNPs do, maybe they only focus on psychiatric treatment, but maybe there is another reason (thyroid?) that is leading to the lethargy and drastic weight gain.
if it is a problem with motivation, i can relate

. when i am depressed it is hard for me to get out of bed. but even sometimes when i am
not depressed, i still struggle with motivation.
my therapist has talked with me about something called "reverse motivation". it's just a fancy way of saying "just do it". i.e., when your alarm goes off at 8am, you're just meant to get out of bed and head to the kitchen. no thoughts about how difficult it is, just get up and move. one good reason i need to get up is to feed my dogs, so now i've changed me alarm tone to my dogs barking, because it reminds me that this is something i needto do - i dont have a choice in the matter; i have to do it whether i want to or not.
my pdoc now makes me meet with him in the mornings so i dont stay in bed the whole day. i am meant to be there at 10am. it is one reason i need to get out of bed. maybe you could schedule some things in the morning that you need to do. i find it difficult to get to work/uni in the mornings, but when it is something like my appt with my pdoc i am able to do it a lot more, because i know how important it is and how booked out he gets.
what things can you schedule into your mornings that will make you want to get up? i can understand work is a difficult one, but surely there are other things you would at least like to do?