Being bi polar isn't an excuse, its a justifiable reason for how you feel and why you maybe make bad choices, sometimes.
Only piece of advice i would give anyone is don't beat yourself up over it, and find something positive that works for you. And accept that you'll have bad days, we all do, they pass. Don't make yourself do something you don't want to do, it creates a negative attitude. Even if its your happy thing, don't force yourself to do it if you're not in the right frame of mind, postpone it, but look forward to it. Build up your next session of it in your mind, relish it. You'll find yourself wanting to get back to it pretty quickly and get a bigger kick out of it.
I'm in my mid 50s and I am what I am. I' ve leant to by and large cope and accept it. Thankfully so have most of my friends and family. So much so that they can actually see positives and upsides to our relationships now, it wasn't always so. They didn't understand me because i hid it away, now they understand me and appreciate what i go through.
Don’t ever feel this is all your fault, if only you can change or that you're a bad person.
Thats not how it works and only makes it worse, find something you enjoy, something you can lose yourself in few for a couple of hours every few days and give it your all. Something to look forward forward to on the bad days, that makes dragging your backside out of bed to face the world worthwhile.
As daft as it sounds go in with low expectations, experiment and have fun.
Do what makes you smile.
Sorry if this is jumping all over the place, last thing for, what ive said works for me , might not work for you, don't think that's your fault, we are all different and one thing I've learnt about this is that not only is each person's experience of it different, but it can be different day to day.
Hope you can take something from my ramblings
Best of luck.