Without a photo of your red bugs, it is hard to know what they are. The only two red bugs I ever see on my tomato plants are red aphids and red spider mites. I haven't had an aphid problem this year, and it is too early here (and unseasonably cool and wet) for red spider mites. You are in a warmer location than mine, so it could be either one.

Compare the bugs you are seeing to the aphids in the photo linked below.

The aphids are about 1/16" of an inch long.

If the bugs are very, very, very tiny....like little red dots, they are probably red spider mites. Red spider mites can be a serious problem on tomatoes grown in hot climates.
One way to determine if they are red spider mites is to hold a sheet of white paper underneath some leaves infested with the bugs. Thump the leaves firmly, knocking the red bugs onto the sheet of paper. If you have tiny red dots on the paper, they are spider mites.

If you have aphids, they can be controlled by good predator bugs like lady beetles, predatory wasps and syrphid fly larvae. Sometimes you can dislodge them from the plant with a sharp spray of water applied to the underside of the leaves. Insecticial soap usually works on aphids. There are pesticides used to control aphids, but I don't use pesticides so can't advise you which ones would work.

If they are red spider mites, you have a pest that can be very difficult to control. Sometimes you can dislodge them from the plants by spraying the underside of the leaves with a very strong stream of water. To get additional info on controlling red spider mites on tomatoes, you can google. For what it is worth, I have had better luck with predatory mites (which are expensive) than with any chemical controls (way back in the day....before I switched to organics).

FYI, spider mites are in the arachnid family, so general-purpose insecticides don't work on them. My dad used to use Kelthane many years ago, but I don't know if it is still on the market and, to be honest, it didn't really seem to work that well.

Good luck.

Here is a link that might be useful: Red aphids