Teething can DEFINITELY affect appetite. Also, the Gerber foods are so bland - I started my kids on grinding their foods up (same foods as we were eating at the table) with the food grinder you can get with a Kitchen Aid mixer - I don't know if you have one - or you can grind some food in a blender. Because it has the food flavored the way you like it, she may enjoy that a lot more and eat more as a result. Plus I think kids don't get turned off their vegetables as much because they don't associate them with being bland if you cook them your way then mash or blend them. My grandmother taught me to mash carrots and potatoes together with a little butter and salt. Boy he loved that! My 8 month old at the time who was hardly eating anything and actually looked kind of sickly. Before I knew it he was eating very well, and filled out and looked much better too. The jarred babyfoods also lack a lot of enzymes the body needs so make sure you have lots of fresh bananas and other things on hand that she can eat by hand.
Also, a tip for teething - freeze some grapes in the freezer (but cut in half first to avoid choking) and give them to her.