Hello,  I have to admit that I only have limited experience with pitcher plants.  I had one in the bog portion of my pond for two years.  I can’t tell much from the photos that you sent that would tell me what the differences from now and when your plant was healthy.  There are variations of coloring in these plants and you did not designate the species.  I have been doing a lot of reading and found some sources that may help you determine what/where the issue is.  The below link comes from the International Carnivorous Plant Society.  There is a wealth of information that may help you decide what may be ailing your plant.  One thing that jumped out at me is that there are multiple references to using only rain water or osmotically produced water.  Since we have not had normal rainfall amounts for the last couple years and much higher than normal temperatures this year, is it possible that you have used water that contains minerals or chemicals to water your plant?  The other thing that we are finding as a theme in this hot summer is that people are watering their plants (in general) about the same as they always have.  The normal amount may not be sufficient in the temperatures and wind conditions we have been experiencing lately.  Plants not getting enough water can turn reddish or brown under these conditions.  The second thing that caused me to wonder is the recommendation of this and other websites to use only Sphagnum peat moss and to be careful not to use ‘other’ peats as a potting material.  Additionally the size of the sand particles seems to be a concern with the larger particles being preferred some sites even suggest the addition of small particles of perlite.  The sources are very specific in the size of the grains and also not to use sand from ocean beach sources.  After reading all this it is a wonder to me that my plant lasted for two years as my well water is loaded with minerals and I certainly did not have the proper potting mixture.  Here is the link you can navigate around on it for other information about pitcher plants and other carnivorous plants.

http://www.carnivorousplants.org/howto/SoilsWater.php

If you are concerned that you plant may have some sort of disease or insect problem please bring in a sample to the Master Gardener Information Desk in the Extension office during business hours, M-F, 9-5.  Phone first to determine if there is a Master Gardener on duty<personal data hidden>.  The Benton County Extension office is located at 4077 Research Way, Corvallis.