Should i need to be worried about my girlfriends s? Need advice?

Ok, well basically her s are really strong! like really strong!! sometimes it worries me! for example when she is approaching she grabs onto me really really tight! and she will shake and literally fall to the ground unless i hold her. Her legs will go like jelly and she will collapse if i don't grab her. She also gets kind of snappy when she s, because if i go to put my back in while she is ing she will slap or push my hand away forcefully until she says it's fine. When it first happened i didn't think anything of it, but we have often and every time she s she is like this! is this normal for a girl to be like that all the time?? I thought It might just be a phase, but it's all the time.