Was this a seizure?

About a month ago, some real weird shit happened.

I was gaming or watching some anime or something when suddenly I blacked out. I don't remember how long for, all I remember is my flatmate asking if I was alright, I had no idea where I was during this. I have no memory of the day before this occurred. We called the ambulance and they took my blood pressure etc and it was fine. Not sure what happened tbh. The next few days every single muscle in my body hurt, it was quite painful getting up and going to work and classes.