Thank you :-)
It said that it was aphids and/or white flies. When the water laid on top of the soil, almost the whole surface of the water was filled with small white almost caterpillar looking bugs
Your description makes me think you think you may have had a springtail infestation. I've experienced both springtail and fungus gnat infestations before, but I've never heard of or seen fungus gnat larvae behaving like that upon overwatering. Springtails, on the other hand, will often float to the top and appear to cover the water. Their populations can grow very quickly following prolonged overwatering.
Springtails aren't a really big deal. They mostly eat organic matter in the soil (or your soilless mix, if you're growing in a container). The only thing you need to do to keep them in check is let your soil dry out between waterings and they will die off.
The brown leaf margins you're seeing might be the result of over feeding (pretty common for a first-time grower). Plants that small don't need much fertilizer at all. Hold off on feeding them for a while and see if new leaves that emerge in the coming days or weeks show improvement.
Aphids are a really common pest, but definitely not a crop destroyer. As Edmick said, insecticidal soap is a great way to keep them in check while they are indoors. Even after it looks like your plants are aphid-free, you still need to treat them several more times because soap will only kill adults. Any eggs that are present will pick up right where their parents left off as soon as you let your guard down.
Aphids are just about everywhere. It's possible they were in the soil you used, but it's more likely that they are just naturally in your environment. It never fails that, no matter how clean my plants look in fall, a few aphids always hitch a ride indoors on the plants I'm overwintering. Around this time of year I start to get complacent and think I didn't bring any in and then WHAM! suddenly I'm seeing then on all of my plants. Their populations explode indoors, when they don't have natural predators to keep them in check.
Are these going to strictly be indoor plants, or do you plan on planting them outdoors later?