Small boat drifting to leeward

Hi, I'm a new casual sailor and I have a very small sailing catamaran (only 8ft long) that I made this summer. It has an issue where it drifts to leeward about 1 meter for every 3 meters of forward distance. I only have a rather small daggerboard on my boat. Is that the issue? What should the boat to centerboard proportion be?
Thanks!