Hi, littlemiss44. Remember that depression is a normal part of the grieving process. You might want to post in the Grief and Loss forum to see what the folks there have to say. What you are feeling is normal.
Losing one's parents is hard. Your dad might be having some depression, too, which is coming out in his anger.
Please don't increase your meds on your own. Talk to your doctor about your situation. And you might find it helpful to see a therapist. Okay?