I agree with everything in here.
here is my 2 cents to add.
Remember, Big beers will finish higher than small beers by nature. This difference is magnified by mash temperature. If I am doing a low gravity mild (1.038-1.042), I mash at 162, and get about 50% AA. With my Scotch ale (1.080ish), I mashed at 152, and got about 70% AA. When I mash my APA (1.055) at 152, I get about 75-80% AA.
Some of this is yeast strain dependent, some is recipe dependent (my APA has 0 crystal), but a huge part of the difference is mash temperature.
regardless, this is a good learning experience. I would taste the beer. It might taste ok. If it is too sweet, I would not recommend throwing in more yeast (Sacc), because I think you are pretty close to the final gravity you are going to get. You might be able to get a brett strain to bring that down a bit further before the alcohol takes them out.