how do you say, "i thought so.." & "do you think so'"

Question

how do you say, "i thought so.." & "do you think so'"

Answer 1

If by "I thought so" you mean "That's what I thought," you could say "Pensaba (or creía) que sí" or "Es lo que pensaba yo."

And if by "Do you think so'" you mean "Is that what you think'," you could say "¿Es lo que piensas (crees) tú'"

Answer 2

In spain slightly different:

I thought so: Eso me pareció, eso pensé yo.

do you think so': ¿Eso crees'