I lost my mother two years ago yesterday and can sympathize. The first few days/weeks are the hardest because in many cases the pain is too fresh and it hasn't hit home yet. It takes time.

I found myself depressed and found that speaking with someone and working out like crazy made a massive difference--other than getting me in shape. Working out helps w/ serotonin production.

You should give yourself some time, but after a few weeks, think about seeing someone if you find yourself getting angrier or sad than you usually do. I would have never said it before, but it makes a difference.