I would definately call the vet in the morning and see what they say about this behavior. I haven't experienced anything like this with lance as a pup. When in doubt, always call the vet. I wouldnt worry about the accidents, even though shes been doing really well, shes going to still have accidents, her bladder isnt fully matured yet.
glad to hear Molly is doing better now! 4 am ...yikes...you both have to be exhausted today!! Just keep an eye on her and if you feel like something still isnt right, go with your instincts and call the vet back if needed. Sometimes we know our dogs/and kids better than the vet/doctor!! I also would keep a log of her reactions after shots so you have notes to look back on.
Was the heart worm medication given at the same time as the rabies vaccination? I've read that rabies vaccinations should not be given with other vaccines. Maybe this also applies to pesticides such as heart worm pills. Just a thought.
Glad to hear all is well!