I never really saw why there was even much of a debate about this--people on either side insisting that it was true or not true that shaving / cutting hair makes your hair grow thicker. Each side providing anecdotal "evidence" for their side of the argument, or scientific studies, etc.
For me it always went like this: Speaking in terms of common sense, how would hair "know" when it's cut or shaved in the first place, to know that its supposed to grow back thicker? All (proper) cutting and shaving involves nicking just the hair itself outside the skin. Hair is dead material. No nerves, no blood supply. By the time it has pushed out of your skin, it is very dead and has no way of sensing that it has been trimmed. For all it knows, it's still long enough for you to tuck into your socks.
If someone, someday can explain to me the process by which hair would be able to detect how short it is (besides the natural process by which a single strand of hair grows, then falls from the skin after a time to later be replaced), or that it has been cut, then maybe I could see it growing back thicker. But until then, I see no reason why it should.
It could quite possibly be a coincidence that you started shaving and more hair began to grow for some other reason at the same time. Maybe your body is changing for some reason. It could be arguable that the power of suggestion alone is enough.