My pot roast in the slow cooker came out kinda dry. What did i do wrong?

i marinated this top round steak in worchesthire sauce for about 8 hours. i put it into the slow cooker with some chicken broth, onions, spice, etc on low for about 5.5 hours. When I went to measure the internal temp, it was about 190. DOH! it was edible just a bit dry for my taste. What did I do wrong? Could my crock pot be too hot? Thanks!