Is it normal some days i stutter

Some days I'll wake up and I notice as soon as I get around people Ill stumble my words and stutter a little and I come off awkward and a little off. It kind of feels like I cant breath and I'm on speed. Then some days I wake up and I'm completely normal. I'll hold a good conversation and have no problems with speech. When I'm having a bad day its like my mind is racing and thinking too fast for my mouth and I'm all out of rythm. I had an amateur boxing career and I'm starting to wonder if its brain damage. I was knocked out twice and had a lot of fights. Its hard some days to socialize because im so off. I wish I didnt notice it but I notice every awkward thing I do. My mind is there but my speech and social skills will be off...