Your having a bad day .. maybe it will be just this day. Use Mindfulness to bring your focus back to manageable bits of time. Maybe writing that letter will be helpful if nothing else it will allow your feels to get out.

Most of us that have Bipolar tend to not share how we are feeling to our loved ones when we are not doing well( we are a stubborn lot) ... Thats the habit that we need to break.. Its ok to cancel plans , its ok to ask your husband to stay home with you.. its ok to ask for what we need..

Distract yourself , dont dwell on "how long will this last". Increase your self care and dust off the coping skills.. Your not alone.. Post here and vent or cry all you want or need to .. Pm if you want.