Irish Dry Stout is not at all thick and syrupy. Think Guinness or Murphy's; very roasty and opaque but medium bodied with a creamy texture and low alcohol. Really need to see your OG & FG.
PS, have you checked your hydrometer to make sure it's accurate?
Beer, if drank with moderation, softens the temper, cheers the spirit, and promotes health.
"Give me a woman who truly loves beer and I will conquer the world." - Kaiser Wilhelm
"I would kill everyone in this room for a drop of sweet beer."- Homer Simpson