Yes, you can probably expect your mother’s payments for repairs to your house to be treated as a gift. You might argue that she made these payments in lieu of paying for her room and board.
A written agreement in this regard would have been helpful (don’t write one up after the fact now, since that would look self-serving), but you could make the argument in any case. Of course, this is assuming that these were minor repairs, not replacing a kitchen or adding a room or a pool out back.
Get more information about Medicaid’s asset transfer rules.