I am having trouble with some of my herbs...?

I'm getting up there in years and the heat gets to me too. I would suggest you add purchased or homemade compost to the potting soil mixture the plants are in. Moisture and nutrients are difficult for the plant's roots to access if the soil isn't soft and loamy; water cannot clay or compacted soil. The newest potting soil mixes contain small beads that soak up water and expand to release the water gradually as the plant needs them. You can also purchase the beads separately and add them to your own potting soil. Lastly, most plants leaves in any kind of soil will wilt in very hot sun and heat. They will recover overnight when the temperature drops. Your herb plants will welcome a little shade during the hottest part of the day. Place them behind a larger plant or provide some sort of transluscent barrier from the hot sun during the day and they should recover enough to produce new growth - don't give up on them, some of the worst looking plants I have seen manage to survive with a little TLC!