It could be considered normal but not if the soil remains wet (as opposed to moist) for long periods of time. That can cause root rot. There should be some new growth somewhere or else it sounds bad.

If you have space in the pot, add a little mulch so the soil does not loose mositure easily. But remember that if it is potted, you will need to water it & fertilize it more often than if it is planted in the ground. If you insert a finger into the potting mix and it feels wet or moist, there is no need to water. If it feels dry or almost dry then water it. Keep it away from air vents that may shoot in its direction.

Once it stabilizes and starts growing again, consider mocing it to another pot. Right now, it is in ICU. I would pot it in a new container, check the roots for root rot and check to see if you need to root prune it (if the roots are circling). Make sure you have drainage holes in the pots (if the current one does not have one, drill some and use another pot when it recovers).

These florist hydrangeas can be persnickety (sp?) and no hydrangea will live long without these potting holes. Spongy wet potting mix all the time is not good for the roots.

Thank you for the response. I will definitely repot it this weekend.

I now think my problem is spider mites. When I got home from work I was looking at it and noticed that the dead leaves were basically wrapped in spider webs. The ones that had just the edges dying only had webs on the edges. I put it in the sink so I could spray it with the sprayer and knocked all of the webs and mites (I hope) off.

Should I get something to treat them, a spray or something, or will hosing the plant off be sufficient? I will post pictures in a few minutes so you can see what I am talking about with the leaves.

This is what some of the branches look like.

This shows some of the new growth with a damaged leaf in the back.

This is a close up of a damaged leaf. I had it sitting outside earlier and it got rained on a little which is why it is wet. You can also see a little bit of new growth in the background.

I see there are still mites on it and they have already begun to rebuild their webs. I really hope I can save this plant.

i think maybe you should try to put it in a bigger pot and put it outside in a place where it will get morning sun and then shade.
good luck!