I dnt feel comfortable around him?

Okay so when I'm around my boyfriend all I do is listen to what he says I never talk , and I get butterflies .. I've never been this way around a boy before so I have no idea why I do around him.!? The thing is I can text him all day and all night . No problem but when we are together I just get all shy and my body kinda shakes and I just wanna run away as fast as I can.!! It's horrible and he tries to make me feel better by puttin his arm around me and pullin my body close to his but that doesn't really help it makes me feel better but not that much.!! Before we went out I liked him soooo much it was hard to explain , I love him and all But I can't go thru this it makes me feel like I cnt be around him and still be able to talk and laugh with him!! Why am I actin like this ?