Hi platinum heart, the reason you feel like "yeah im gonna work out lets get ready" is due to adrenaline a small shot of it released in to your body. Here is what you should do even when you don't want to work out force yourself to because as you may well know when you exercise it releases tge hormone endorphins think thats spelt right lol. Once this is in your system you will restore the same feeling as before. Hope this helps.