Lately I've been feeling tired and loss of interest in things
You should go out and enjoy some time with friends or family. OR maybe your just getting tired of your day in day out days in that case try changing things up a bit.
Your probably under alot of stress. Try relaxing more.
You need to put a pep in your step. Do things that interest you. Listen to upbeat music, get plenty of sleep, eat good hearty meals.
u need to have a better diet