Things to do when you have a safek brachos:
1. Shinui makom (change of place – go outside). Note: this does not work for Mezonos or Hamotzi, so it wouldn’t help here.
2. Have someone else be motzi you
3. Make a bracha on another food that you definitely did not have in mind the first time (although whenever you make a bracha on food, l’chatchila you are supposed to have in mind that it should cover any other food w that you may eat that has the same bracha. If you do that, then this suggestion would be impossible in most cases. However, in this case, if you made a mezonos on any “regular mezonos” it should be okay since your al hamichya certainly covered any “regular mezonos”