Hi - I taught riding lessons through college and remember being exhausted. I took to sitting on the rail for the big group lessons and giving instruction to each rider as they came up and passed me. If I needed to continue chatting with them, I would hop off and walk next to them. I would also have the rider circle me so they could hear my instruction and I could stand in one spot. Riding a number of horses a day also wears one out. My horse is green and I have recently started her under saddle and every time I ride, I'm exhausted! I know I'm heading into a physically and mentally exhausting endeavor every time I get on her. So, no worries, what you are experiencing is totally normal. When I find myself overwhelmed riding and battling the feed buckets and not wanting to run or ride my bike, I just tumble into bed and tell myself that my 'inactive' day is a lot more active than most people's most active days. Give yourself a break and you'll get that energy back and feel like riding your bike and running again soon...