Any speech therapists who will advise me please?

[Mirrorball]

My little boy has just turned 3 and for the past 3 weeks has been doing the following regularly enough for me to be concerned, for example:

"My -my-my-my-my-my-my-my-knee-knee-knee....." at the start of sentences. The repetition of the first or second word can go on for up to 8 times.

It is the words he is repeating, not the first sound, if that makes sense.

Today he got frustrated with himself for the first time while trying to get a sentence out and stopped... it broke my heart.

I will be going to a speech therapy drop in with him next week but just wondered if there were any speech therapists who know anything about this - is it something which will just eventually stop once he's less tired/busy... or should I be seeking professional help for him? He is a fast little boy, always rushing around and bumping into things, this is like he's rushing to talk and his brain is working faster than his speech?

bumping

This could be seen as normal so don't panic or react to the stutter with any disapproval or even a slight non verbal facial expression as this could worry him and make him anxious which can lead to the stutter developing further. Most kids go through this and so long as you do not pathologies it i.e. give it a name or discuss it around him, it's very likely to be a normal phase and simply will fade away. Only if it persists would I seek help.
Btw I'm not a SALT