If I remember correctly, the wifi in question is public access in a
apartment or condo right? In addition to just being clogged by everyone
trying to use it... There are various attacks out there that can disrupt
wifi signal without having any access to your account. One of which was
recently published as an android application, where the phone connects to
the network, spoofs the router, and drops all data requests from other
machines.

Now I don't know much about the technique or app other than what I learned
reading about it recently, but it was an interesting read anyway.

I don't see how anyone would be doing what you describe on your OS though.