Bled first time sex

I bled a lot during my first time having sex. I've never seen so much blood in my life. It was extremely painful. Im not sure why. Is it because of size? My bf is 6'2" and I'm 5'3" so I am a tiny person. Now our sex feels amazing and it only hurts when he goes really rough and hard. I bleed sometimes a little when he goes in when I'm not wet yet. Anyone else experience all of this?