Not the greatest week. Tuesday's planned workout got cut short due to horrible humidity and heat (no argument here). The weather was better later in the week, and I had a solid hill workout, but then I didn't feel great for Sunday's long run, pulling the plug when I started to feel like I was straining. I hate pulling the plug on hard runs, but I gain nothing by running myself into the ground. I've also got some sinus pain, and mild head-spinning symptoms when at rest (weirdly, I only notice the head-spinning when I'm NOT running).
There's several potential causes here - the humidity is one possible cause; others include not getting enough fluids, not eating enough, overtraining, fighting off a bug, or allergies. I'm suspecting it's one of the last two - I know of at least one other friend who's been fighting allergy symptoms this week, and head spinning/ dry sinuses are often allergy symptoms for me. OTOH, Brian had a few days of sinus issues, so it may be a bug that he's given me.
Regardless of what the cause is, the best first response is rest, eating well, and drinking a ton of fluids. Can't hurt, especially since I'm between training cycles, and there's no need to push stuff if I'm not struggling. So that's my plan for this coming Monday, at least, and then I'll see how I feel.