I agree with the others., this could be something incredibly serious. Please get help ASAP!
Hello~You really need to go to the ER, this sounds like a situation that needs prompt attention.
Hi there -this is a potential emergency situation, and I urge you to go to your nearest emergency department. Brown vomit is indicative of blood - "old" blood, which may be a sign that you have internal bleeding in your stomach. Please do not wait - get examined as soon as possible.