Yes, you need a very weak solution of fertilizer for the plants, but they probably needed some fertilizer.

Sorry, the picture quality isn't too good (i take photos like that myself, lol), but I don't see normal fertilizer damage, which would include drying and crisping on the outside edges of the leaves.

My first suspicion is that you might be overwatering. Actually, I feel pretty confident that is what is happening. I know that peat pots dry out fast and it's tempting to want to keep them moist to downright soggy, but I would let the soil get dry in between waterings. Tomatoes really hate too much water. They hate having wet feet due to sogginess.

If the roots are coming through it's time to get them out of the water. Do not leave them in water. You may want to transplant them into a larger container with potting mix (not topsoil or garden soil) or put them into the ground if they are ready. Water them only when the soil has dried out. Stick your finger in the soil a few inches down; if it's still moist, don't water.

It's okay that it has been cloudy and they have been deprived of sunny skies. That should not cause any problems.

They don't look too bad and should recover when they've had a chance to dry out for a few days or so.