Hoping that this will be of some help to you! I felt exactly as you did when I was diagnosed (although slightly relieved at the same time as I finally had a name for my 'craziness'). I'm 33 now - I still find BP difficult and I'm not going to lie to you and say if you do x, y, z it will all become easy, but hopefully some of this will help.
Being BP has brought some incredible changes to my life. Eating healthily, getting regular exercise and relaxing whenever possible have made me look and feel better than I did at 21. It also means that my episodes now are not as bad and don't last as long. Try and look at healthy living as a good thing - our bodies do work better on good food, just like your car will run better if you look after it and top up the oil and water.
It's made me look at my life and appreciate, not only the things in it, but the days I have when I feel really well (and when I'm well now, I'm really well because of the healthy life style). I feel the sun on my face in a way that a person who's never looked death in the face (and lets face it, most BP's have been suicidal at some time) possibly could. The superficial stuff doesn't bother me so much any more. I'm much more selective about the people I spend my time with, and what I spend my time doing, because my time is more precious to me now than it used to be.
Medication is a big problem for all BP's because of the side effects. You can look into complementary treatments - they're not necessarily a replacement for meds but they can make you more stable, meaning that you need to take less medication, so suffer fewer side effects. Things I have found helpful are:
Counselling - long-term to deal with all the stuff that's happened before, cognitive to deal with the here and now and make coping day to day easier.
Homeopathy - doesn't stop me getting ill, but does tend to sort me out when I'm having an episode. I've just got through a mixed episode on a homeopathic remedy and a tiny amount of Olanzapine, so the side effects weren't too bad.
Any kind of massage or hands on treatment is good for stress.
Emotional Freedom Technique - it's kind of like acupuncture without needles - I've found this useful, particularly during a bad spell.
Healthy eating - a really good book called Optimum Nutrition for the Mind by Patrick Holford gives lots of advice. He runs a really ethical vitamin company called Higher Nature - they're great for supplements and you can get lots of advice from them.
Exercise - yoga is fab, being outdoors helps (sunlight), anything that gets you moving is good for you to do and helps relieve stress.
I used a Lightbox one winter - that seemed to help keep the depression away.
I completely understand where you are right now. I've just come through a mixed episode and believe me, if someone had told me they could stop it all forever by cutting both my arms off, I'd have handed them a saw. Hang in there - it's a major illness and it will take time to get to understand it and deal with it, and it will never be completely easy. I find my well times outweigh my ill times now - three years ago it was completely the other way round and had been since I was a kid.
You've got friends here who understand as well!! Make use of us, we're thinking of you xx