I'm not bipolar- but I understand what you're going through, my mother suffers from "extreme" bipolar (I can't tell you which type because she's never been diagnosed because she doesn't think she has a problem). So first off, congrats on recognizing this & getting a diagnosis, that's a big step to take and not everyone is willing to recognize something is not right.
I do however suffer from adult ADHD, which can put some strain on my weight loss goals- because I often start a task with every intention to finish it, but then get bored with whatever it is & loose my motivation. This applies to weight loss & just about any daily activities. (for example: I'll say "ok I'm going to do laundry today" and I'll end up washing 5 loads but then it's just not stimulating anymore so the clothes will go unfolded for a week, or longer!)
I would highly recommend getting started on a routine. Perhaps, set your alarm clock for the morning, and just force yourself to get out of bed. Easier said than done, but if you can just pull up some motivation to get up & have a cup of coffee- at that point you'll probably be more likley to start your workouts since you're already up and moving. And on those really tough days, just think of getting your workout "overwith"- after you complete that, just think- you have the rest of the day to vegg out.
I know my suggestions sound real simple, but this really works for me- and trust me I am the biggest procrastinator, ever! I hope this works for you, but just focus on having a routine (like maybe monday through friday you get up at 8 am) no exceptions. Good Luck!