It's totally normal to not feel like working out. Motivation can't always be relied upon, it comes and goes!
Sleep, stress, not getting the results you were after often have an impact on your motivation levels. It is important to keep these factors in mind and do what is best for your body in the moment.
Often we don't feel like exercising because we have been too sedentary. However, we actually need the energy and enorphins from exercise! Have you ever noticed how you have MORE energy after a workout than before? This is your endorphins being released! Exercise increases our endorphin levels, heart health, sleep and focus!
HIIT workouts in particular are great for releasing endorphins, even when you might not feel like it. If an intense workout is too much for you in that moment, start with either a walk or other low impact exercise, this will most likely give you the energy to do more!
Don't expect motivation to just be there, once you stick to a routine of working out, it starts to become a habit and you'll be less reliant on motivation.