Dude i feel for you man... just remember that your dad is watching over you, and that you need to live the life he would want you to live. Stay strong for him, and stay motivated in life. i have found that being active has helped my anxiety/depression immensley. I began running every day, and I noticed that I was beginning to get a hold over myself. If you are not already seeing a physcologist, it would greatly benefit you to start. Good luck man, and stay strong. People will tell you to take this medication, take that medication... i would say that the best medication for anxiety/ depression is to tell yourself that you can come out of this situation stronger than you were before..
My sympathies for you loss. I can't imaging what you are going through. I'm terrified at the prospect of my parent's eventual death I have ordered my mother that she can not die. (don't have any idea how well THAT will work). In addition to what Paxiled suggested (and he can tell you we don't always agree, but here I do) I would also suggest a support group. It helps when you have other people who can at least relate. Work with your stomach, not against it. Eat when you can manage it, even a little. Look at getting some protien drinks, like Ensure or Boost (the weight loss shakes, while having nutrition tend to have a lot of caffiene and that can make anxiety worse) to supplement small meals. If you can't eat when you get up, trying taking a relaxing shower or bath. When you feel you can eat, do so. This is what I have been doing lately since starting ADD medication since it tends to decrease appetite. I have to get something in my system since I am nearly type 2 diabetic, and "forcing" myself to eat tends to have disasterous consequenses.
Remember too, this is a huge loss and the grieving process takes time. I hope this helps!
This is normal -- instead of letting your grief build up by repressing it, you're letting it work itself out. I do encourage you to stop the mj at least while you're grieving -- it tends to exaggerate whatever we're feeling, so it will just push you to feed on your sadness more. This could be useful if done with a grief counselor, but since mj is illegal now, we can't really use drugs that way anymore. But seeing a therapist will help speed the process of grieving and coming out the other side. Peace.