I decided to try a treadmill threshold run. Usual routine of 2km warm-up, then whack the treadmill up to 18.5km/hour to lift into the threshold zone. Normally it takes me at least 10 minutes to get into this zone but today it took less than 3 minutes - and the HR kept rising. Sweating buckets, feeling a bit dizzy I pulled back the speed but the HR was still high so after 5kms I pulled the pin (16:37). Feeling pretty awful I took a break and then ran 3 slow kms to finish with to give me 10kms for the day.
So clearly I'm still not right so I'm going to take it easy for the rest of the week. The stomach is still a bit off and the throat feeling a little lively so the signs are there.