It may be difficult to see or know what to do but see why you trusted this person when you shouldnt have, without blame shame and guilt. and then think.
Who is available in my life who can be supportive, who is there that my preconceived notions are missing, then look at your previous mistake and see how different the person you saw yourself needing is from the person you actaully do need.
Then seek them for help or support. I guarrentee one of these people is the side of yourself your lost faith in (due to preconceived notions) and the other has probably either been there for years or is right in front of you everyday.