McBimsWitChi

As far as I can tell, youre not doing anything wrong at all. Its just that the colony ship is used up whenever you colonize a planet. This is a part of the game, you have to build a new colony ship for each planet you want to colonize. Same thing with constructors, you have to send a new one to a starbase each time you want to upgrade it. Hope this helps.

I had a similar Problem. But just like Erynnios said, reloading my game and then pressing "Enter" worked like a charm, and then the turn button returns and you are free to contine with your galactic domination