No, I get fresh. I get tired if I don't cycle in the morning.
20-25 minutes each way. Which is slightly faster than using public transport.
I get tired if I cycle more than 40-50 km in one day. The longest I've cycled in one day is ~64.6 km, but ~4 km of them was in the evening, so 60.6 km is the longest I've cycled without breaks.
Also cycling is good for your healths.