Passing out after T shot?

I just did my shot, my needle size is 25g but it hurt a lot going in, it has never hurt that much before. I do subcutaneous in my glutes area. After my shot, there was a lot more blood than normal, then I felt really dizzy and had a quick nap I guess. I was standing during the shot, sat down after I felt faint. I think I hit a vein or something, I'm not too sure.