Acquire financial stability so I can quit working.
Pray to God, because stopping time for a day is clearly beyond the scope of science.
Which God. Could be the devil or that evil villain in batman with that stopwatch.
Look for the incongruous Police Box, because clearly something broke physics and if I'm the only one moving, I certainly don't want the monsters to find me, first.
Beware the Weeping Angels.
I'd probably go to a secluded beach and pamper myself with no tan lines, good music, a good book and some lovely drinks for the day. Just me, the beach, the waves and the sun enjoying some one-on-one time together. Afterwards, watch the sunset, go home and eat a nice meal and take a bath. Just a decompress day all to myself.