I know its not helpful at 10pm on a Sunday night, but you should go and see your doctor tomorrow and tell them how you have been feeling, they might be able to change your dose, give you a different anti-d, or send you for some counselling too. I'd get an early night now, sleep is so important for fighting depression. I find getting excercise every day helps even if its just a walk around the block, and taking multi vitamins and being careful with my diet. Do you live with a partner? do you have kids?
If you try and get to sleep now, things might be clearer in the morning,
If you feel like you might hurt yourself or someone else, its best to call your out of hours doctor or go to A and E....