An Upsetting and Blurry Discovery

I made an upsetting and blurry discovery this weekend. My primary lens, a Sigma 28-300mm f3.5 hyper-zoom, is now defective. One or more of the glass elements must be out of alignment, as all twenty-seven photos that I made on Saturday with this lens are all slightly out of focus to the same level of softness. It’s not a problem with my Nikon D80 or D70 because photos that I made with my other lenses on those cameras are tack sharp. Everything I shoot with the Sigma is blurry. This discovery was really upsetting to me as I had shot two-dozen photos of a male and female barn swallow that had taken up residence in a birdhouse at my parent's home. When the sun fell on the male just right he had beautiful iridescent blue feathers on his head and down his back, and he was a poser! For a few shots he faced me straight on, then he turned and gave me a nice profile. Both the male and female allowed me to get within eight feet of them and I had nice individual portraits of both, or so I thought until I got home and downloaded the images. The focus
is soft on every single image. I was shooting at f11, so I had a good depth of field, and they looked sharp in the viewfinder, but the final images are all ‘fuzzy.” This is very upsetting to me, but it's best that only a couple of dozen images are lost than the couple of hundred from our upcoming Outer Banks vacation. I would have wanted to die had I gone on vacation, shot several hundred photos only to come home and find them all out of focus. I think that would have pushed me so far over the edge… well, I don’t want to think about it. I would have been devastated. Better to loose twenty-seven pics of a barn swallow, than a weeks worth of vacation images. Time to get a replacement lens.