Should i go see a doctor for loss of appetite?

I don't get hungry anymore lately. I can go all day without eating, and still no hunger. I only really eat when i force myself too. Like today i ate a pack of Top Ramen. And a little bit of hamburger helper. I used to eat a lot all day every day, but starting a few months ago i my eating habits have dwindled. Also in the last 3 months i have lost 15 lbs. With little to no exercise. Should i go see a doc?