Pamela, it is Fall. Lots of things slow down, go dormant, die back or simply die if they are annuals (like your Petunias). Most plants have a dormant season unless they are real tropicals. Do not stress yourself about plants that are just doing what nature intended.
Most of us adjust to the cooler seasons of winter by growing "other" plants that do well indoors, or here in FL for me, I can grow annuals that like cooler weather, like Nasturtiums outside from now until about May. You need to "go with the flow" of the seasons to become a real gardener. Don't try to fight Mother Nature too much. But for instance, if you'd like some gorgeous flowers that will bloom outdooors through the fall and sometimes even survive winter, try fall Pansies. They should be on sale at your big box stores about now, or better still, try a good nursery near you for better selection.
If you'd like to share your pictures, there are lots of forums here especially for that and you'll get to chat with lots more gardeners if you make use of the other forums, too. This forum is for specific questions and answers.
