This happens every single time!! If I take a break from working out (ok, several months), and than try to get back on track (with an easy, low-impact work-out), within a few hours I come down with a cold??!! Has this happened to anyone else? Does anyone know WHY this happens?

This last time all I did was spend 10 minutes on a rebounder and spent 5 minutes doing some gentle stretching - and by the end of the day I had a very sore throat. By the next day (today) it has blown up into a fully functioning cold!