I've heard/seen tomato plants droop for a little while after planting them in bigger pots. When should you worry about your tomato plants after this happens?
Wait 10-14 days. If you see new growth, it's fine. In the meantime make sure to water consistently every other day r when they look droopy, sometimes you might have to water twice a day (I know I did). When you water, fill the pot with water until water comes out the drainage hole. But this assumes your temps have highs of 80F or so.
Generally when the temps hit 80F on any day, I water them really well. When high temps start reaching 88 I often have water the twice a day. If they look droopy, they are telling me they are thirsty, and I water them.