Can depression have an impact on your health in terms of energy levels? think i suffer from depression and..?

...and always try and hide my feelings and put on a happy face. But sometimes i wonder if the emotions i feel and intensity of it i feel on a regular basis and constantly covering them up can have a negative effect on my physical health because i'm always tired, and sometimes feel so exhausted to the point where i feel like i have barely enough strength in me to fulfill my tasks. sometimes i go in a daze and feel like i'm there physically but mentally i've gone in a daydream because of how tired i am and just tune out everything around me. i don't work long hours (5/6 hours max a day), i eat generally healthy except for the odd junkfood now and then..and have lately for the past month started exercising 6 days a week to get in shape for summer (alternating one day weights, one day cardio etc). Sometimes on my days off when i'm not working i'll have a lie in and sometimes spend my whole day in bed...i'd go to sleep midnight-ish and wake up late morning, eat something then go back to sleep until 3 or 4...