Do you still feel ''attached'' to your partner, like something you just cannot get out of your mind 24/7? Do you lie at night worrying about her? I think that is how you are feeling anyway. Even if your spouse displays the symptoms of a certain illness such as bipolar in this case don't take it as face value. For example there was a time my psychiatrist thought I had bi-polar and even the psych was even having difficulty diagnosing me, I actually have borderline personality disorder just some of the symptoms from both illnesses are similar.
Fair play to you for even attending a support group, I can't begin to imagine how much you love your partner. You need patience and to try and move past this until she does come back, keep your days occupied if you can and keep talking because it helps get all the emotions out. I'm not saying forget about her but just to look after yourself as well.