My two indeterminate Roma tomato plants have started withering more and more each day. There has been more rain that usual recently but it's a very quick turn. Please can someone look at the photos and tell me what's wrong with them? There have been a few leafminer infestations during its life and it has some new random small holes in some of the leaves, but the leaf withering / curling is across the whole plant.
Even if these plants are a gonner I don't want to make the same mistake with my others.
Thanks!

How often do you water? The plants look very dry to me, and in those small pots would need watering on a daily basis, or even several times a day. Tomatoes want to be kept evenly moist.

I water once every 4 days, as they're also getting some rain (sporadically). I also suspect that this might be related to OVERwatering as the leaves started curling inwards when it had been raining a lot.
I also read that tomato leaves curling upwards is a sign of too much heat, not enough water, but downwards being related to overwatering/root rot - Is this correct?
Thanks!

I don't think that's enough watering, what are your daytime temps like right now?