It may be too late for this, but you should allow the leaves to turn yellow before you remove them.* They will feed next years blooms.* Also, some varieties of tulips that have been forced for blooms don't return to bloom again.* Do you know the named variety of your tulips?* This first article is a bit long, but both should be helpful.
When weeding, the best way to make sure you are removing a weed and not a valuable plant is to pull on it. If it comes out of the ground easily, it is a valuable plant.