If I play an action card as an action and another player plays sabotage on it, can I take another action or is my action considered taken already?
From the FAQ here: http://new.fantasyflightgames.com/ffg_content/Twilight%20Imperium%203/ti3faq2-2-4.pdf
Q: Is an Action Card that has been sabotaged considered played?
A: No. For example, a “play as an action” Action Card that is sabotaged does not use up its owner’s action.
So yes, you should be able to play another action.