I would like to help but I don't know if we can develop new symptoms while augmenting an antidepressant. What I know is that often, new symptoms can appear with time.
I would ask my doctor. But if it can reassure you, I took up to 200mg of zoloft in my life and nothing bad happened to me. Something may interest you too: I got more side effect while raising the dose at the start, than later. From 25 to 50 it was very obvious. 50 to 75, less obvious. 75 to 100 or more, nothing to notice really. So it may be easier to raise later than right now. I say "may" because we are all different.
Your yawning is clearly zoloft for me, and because everything happened in the same time, I would say that it's all zoloft.