Where did it come from?

I had worked for days getting ready for my out of state relative to come visit and stay at our house for a week. I was exhausted by the time they had arrived. We had many plans for the week and I wandered where I would find the energy to do them all along with an already busy schedule I normally have all week. Not to mention having to keep the housework up so the house remained clean while they were here. But everyday I had the energy even though I didn't know where it was coming from. If I had this much energy to go all day while they were here why didn't I have it when they weren't here? If I knew I would get it for everyday but I have no idea where it came from but I am sure glad it came while they were here. I believe it is always inside me but it only comes when there is so much that needs to be done. If I Changed my mindset I would find it each and every day but I am just too tired to even want to be that busy so when I know I can get away with not doing anything I don't reach deep inside to find the energy so I can just relax when I can.