I'm always tired an sluggish. could this be a thyroid problem? what are the symptoms of thyroid problems?

Possible: It's possible. Get a blood test to find out. Hypo (low) thyroid symptoms: fatigue, hair loss, hoarse voice, slower speech, depressed, brittle nails, dry skin, feeling cold, constipation, weight gain/can't lose weight...For hyper (high) thyroid: feeling nervous, fast heartbeat, weight loss, feeling hot, trouble sleeping, feeling anxious, sweating heavily, muscle weakness, frequent bowel movement...

Thyroid: If the thyroid is under active it can cause multiple symptoms including: more sleeping, weight gain, change in skin texture, menstrual irregularities, not being able to stand the cold, depression in severe cases, easily fatigue, constipation and others.