Hi i had 6 months off work and did a lot of cardio 6 days a week to build stamina. I was doing really well, feeling good but was sleeping 8 to 10 hours a night. Now back at work 4 full days a week so Far for 5 weeks. But became unrelentingly tired with aches all over for last 5 days. Yuck. Heart palpitations at night abit. So maybe gone backward on the way forward. Feel exhausted. Anyone else increased their activity and then felt smashed?