What are the stages of grieving and hurt?

Recently I've found out my boyfriend was sleeping with my best friend and I was with him for 2 years. And when we spilt up, them two got together. Now, when I found out, I was distraught, I couldn't cope and ended up putting myself in hospital, but as soon as I got out, everything changed for me, I was still hurt, but happy at the same time, I didn't shed a tear over it... for about 2 weeks. Then all of a sudden it just completely hit me! I've been crying everday and night, and it's constantly on my mind! Is this the stages of grieving? Is there a calm before the storm? And once the storm has occured it will clear up? I've been hurting really badly for the past month...