Do you have access to a teacher who has been instructing you? If so, the best idea would be to ask that person.
Otherwise, you might also consider watching the breath through some other tactile evidence of it, such as the rising and falling of the chest, or the sensation of wind moving through the throat. Fortunately, you're still breathing. As long as you have breath, it can continue to be your object.
What everyone else said is good, too.