is it normal to feel jealous?

So there is two girl that I am friends with.
They are very close to each other which make me feel excluded.
For example today, A told me that B hates me and then according to B, A told her I hate her
And well we kind of solved it, But A got angry at me because I told B what she said
and B gets angry at me because I didn't ask her if it was real. But the important thing is, they didn't get mad at each other at all.
And they always hang out, go to each other place, put a lot of picture on facebook, and im not in any of them. And yes, I get jealous.
I want to stop feeling this way because it's stressing me a lot and I couldn't work, couldn't sleep.
Please someone tell me how can I get out of this feeling?