post-run nausea?

silencioesoro

I've been slowly increasing my mileage on the treadmill per month (extra half-mile per month), and I tend to change up the speeds. But yesterday and last saturday, I've been feeling rather nauseous after my run. Last night was the worst I've felt in a while.

What can I do to prevent that from happening (as bad, I can handle little nausea here and there) again?