Why are my gums bleeding?

I use the colgate 360 toothbrush..well they came out with a new type of colgate 360 toothbrush and ever since I started using it or a couple days afterwards my gums will bleed. Not just a little but a lot. In the one area it will look like its just pouring or gushing out and when i spit its all blood mostly..can anyone please tell me what the problem could be and what I should do to make it stop? thanks