Why are my seedlings so small?!

[loulac]

Originally Posted by ARgardener

I always just heard people talk about not keeping this all too wet and I've always been a bit paranoid about damping off.

From the big variety of approaches you have read here you certainly have noticed that tomatoes are tough plants that can practically withstand all kinds of treatments.
Watering tomatoes is a complex topic. In industrial greenhouses tomatoes grow on glasswool constantly soaked with a solution of fertilizers. In smaller installations gardeners don’t water each pot one by one but pour half an inch of water in the storage container, wait till the pots have sucked up the water, then water again when the mix is dry. We can often notice long roots growing through the hole at the bottom of the pot, they bathe in water most of the time and are perfectly healthy. The trick is to keep most of the roots in a gas permeable mix, the roots need oxygen. Here lies apparently a major drawboack of your mix that becomes as hard as concrete.
You are not a professional, you don’t have to make a living with your tomatoes, just enjoy growing them, a mistake from time to time is just a part of the game.