Harmonic balancer comes off

Recently, our 318 started making noise when running. Ever since we got it running , the timing has been weird. After starting it up one day, the car shook more than normal , and was making a funny noise. When we took all the belts off, to get to the harmonic balancer, we saw it was loose (that was our first thought when we heard that noise. I was under the impression that a tool was needed to take off / install the harmonic balancer, but the harmonic balancer can right off. What should be our next step? Thanks!