Help!

Hey! if anyone could help me that would be perfect, on my bass guitar i just broke my top string (e in standard tuning), and it seemed to cause a lot of problems, it made all of my strings buzz up intill around the 7th fret!! this is really bad concidering, i cant afford a new bass, and i dont know what the problem is!!!! PLZ REPLY
 
All the strings put tension on the neck of the guitar, so it naturaly bows out a little. When one breaks, some tension is relieved, so the neck straightens out a bit. Imagine an archer's bow. it gets straighter if the bowstring is removed. So with the missing string, the neck lays back and the rest of the strings are now closer to the neck so they buzz.

Replace the missing string. Tune up to proper pitch, and it should fall back into line.