Sorry to hear you have that problem. I'm a stutterer too and it seems like we have our 'good' days and 'bad' days when it comes to speech just like you mentioned. It fluctuates between fluency and disfluency. I still dont haven't found out why this happens but a couple theories I have is how many hours you sleep and how's your anxiety level during that day. I find it that sometimes in the mornings I can just feel that im gonna have a bad speaking day. As for what you can do, im afraid I just dont have the answer but I hope the info I provided for you has given you a little insight. But don't give up, not matter how bad you think you may sound.