[Henry Schmidt]

Small claims courts are courts of equity not courts of law. The judge can make shyt up as he goes along. Put your claim / evidence in written form so your story is easy to understand and don't accuse the plaintiff of wrong doing just be clear about what your side is.
I believe that he (the plaintiff) is entitled to recover any losses he uncured by virtue of your early termination. If he rents the space, his claim for rent is mitigated. If the space was empty for any time, you owe that rent. If the space rents for less, you owe the difference. If the contract calls for legal fees and your state allows for them you may be on the hook for those as well.
Good luck