I can definately relate to how you're feeling, and I'm sorry you're so down. It really sucks having to suck things up and pretend, I know. I do it all the time for the people in my life that I love publicly. I also do it when I'm working because no matter what problems I'm having, I have to be a positive role model for my clients. They come to me to feel better, believe it or not!
The candles and trying to replace your thoughts with something negative are a great idea! Do you have any hot tea? My accupuncturist "perscribed" a tea with valerian root along with an herbal tincture made by BACH Flower Essences. I've been using both at night for the past 4 days, and its really helping me to stay calm when I'm at home alone at night.
I don't know what your particular issues are, but do know that there is hope for tomorrow. I'm getting by right now by telling myself over and over again that there is a light at the end of the tunnel