How old is Zach? If he's over one and had them last year already, I really wouldn't give again. I personally don't believe in yearly vaccinations and find them totally unnecessary. Most vets follow AAHA protocol of every 3yrs now.
And yes, Jackson had a terrible reaction to lepto as a 12 week old pup. We now give benadryl before giving rabies shots just to be on the safe side.