Is this a normal part of grief?

I just lost a friend just over a week ago, very traumatically, in a very terrible car accident. I’m 20 and am working a summer job with other university students. Lately I’ve been very irritable at work, i don’t want my coworkers to talk to me because I get pissed off very easily which wasn’t a problem before this happened. I just get pissed off so easily, I have been very upset at work too, having to take walks because of random spurts of crying. Just wondering if the irritability is a normal part of grief?