Brain fog

There's something seriously wrong with my brain. I had a three day migraine last week, so I went to urgent care and got a shot. Ever since then, I've had major brain fog.

For example, I just sent the pitch for my story out and I have no idea who I sent it to. Well, now I do because I checked, but I had no idea if I even entered the e-mail right. That's not normal, not for me.

How long should I let this go on before I all the doctor?