I've lost a very close friend to suicide and I know how you feel. She was also my go-to support friend. I spent months just howling every chance I got.
Yes, I think anger is normal. They've deliberately taken an action that made you feel this way. They could have chosen another course. It is additionally painful because it feels so unnecessary and they feel like they've just slipped through your fingers, as if you could have grasped them if you were a tiny bit quicker.
The most helpful thing someone said to me is to picture your life like an island or landmass poking out of the sea. This is a big landslip and the ground under your feet has literally given way and it's terrifying and raw. But in time that just becomes the new landscape, flowers grow up over the mud etc. And you can extend your life (the island) in different ways, even if that bit is gone forever. I suppose the gist is that it's not about waiting for these feelings to go away, but learning to live with them and eventually feeling your life is full again from other sources.
It's 8 years since my friend died and I still feel a profound sense of wrongness, injustice and a bit of bitterness about how she died. But I have come to terms with knowing she felt totally hopeless and desperate and that was the only way out that she could see.
A positive thing you can take from it is seeing how much every person has a network of people around them who are bound up by bonds of love because when someone dies suddenly like this, all those connections are kind of highlighted by pain and you can see how far the ripples spread. Everyone is important, and vulnerable, and precious. You can use this to teach you how to appreciate the world around you and the people in it.
Use the Samaritans if you need to talk, or reach out to friends - even if you don't feel close, you might be surprised at the response.
Our bodies also hold on to grief - exercise (walking, running, swimming, cycling) can help your body to get some of the tension out, help you sleep better etc. A long walk somewhere green can be a really important way to look after yourself. A shock like this makes your body go into crisis mode, you need to take care of it.