I'm glad you're feeling better
From the little we can go on it sounds more like a possible poltergeist, a manifestation of your intense and usually negative energy, rather than another being/spirit/demon etc. They're usually experienced by teenagers and have a tendency to appear as big cats or dogs/wolves; but as you said you first experienced it as a teenager when going through similar emotional stress as you are now, so maybe it was a trigger and coupled with your memory of it happening before it happened again.
Hopefully that's all it was and you're healing