Out of control speeds and altitude when going around

[LukeFF]

I don't know if it's me, but I'll try to explain it the best I can:

ILS landing, had to perform a go-around. Raised flaps and gear, trigger the TOGA button, set my new altitude to 5000 feet. Plane instead goes into warp drive, over 400 knots, 7000-plus feet per minute. Autopilot and autothrust were enabled. Even when I tried altitude hold or manually setting the vertical speed to -1000 fpm to try to get the thing to stop climbing, it just kept going and going to about 10000 feet. It was just unresponsive to any sort of altitude changes. Finally somehow it leveled off and started descending, and we got back down to where we needed to be. 

Unfortunately I had to fly another go-around, and the same thing happened again. At this point I just had enough and shut the thing down.

Did I do something wrong in my procedures here that would cause such a thing?