I am sorry you are feeling so sad. It is hard when you feel there is no way to escape from your sadness.
Changing your thoughts can help. Although your daughter is away, thinking about that can make you feel worse. Even if you feel very alone because of it, you are very cared about. Your daughter may not be with you but she is still thinking of you. Other people in your life care about you. I care, your therapist cares and anyone else helping you now cares as well. Think of those who are in your life. Allow yourself to be wrapped in that care, like a hug.
It may be hard to move but if you do something small, it may help. What comforts you? Tea, a hot shower or bath, something to eat, etc. Take it slow but push yourself to try to do something.
If you like chocolate or you can tolerate caffeine, try a small amount. Both of these things can improve your mood and chocolate can increase endorphins, which will lift your mood.
Try focusing on anything outside yourself. If you focus on your feelings, you will feel worse. Do something intellectual such as read a book, watch TV, play a computer game.
Write out how you feel in a journal or even on a piece of paper. Sometimes the act of putting your thoughts on paper can make them less intense.
No matter what, keep in mind you are not alone. No one may be with you now, but that does not mean no one cares. I will keep you in my thoughts (and if it is ok, my prayers) tonight. Remember, this will pass and you will feel better. It's only a matter of time.