Stressed and worried for the future...

So I have 3 beautiful children (soon to be 4 beauties soon) I have my 7 year old son, 4 year old son and 2 year old daughter and baby boy due this Sunday.

I love my kids unconditionally I would do anything for them, but my 4 year old son is dragging me down quite hard!

My 7 year old developed all on time and is similar to a text book child for his development other yhen the over talking but I put that down to his intelligent and just wants to know so much to get that knowledge which doesn't bother me.

My 2 year old daughter is dry during days just got the nights to sort and her speech is incredible for a girl her age and she's stable on her feet running or walking.

But my 4 year old is still wetting and pooping himself day and night, he don't speak clear for e.g Thank you sounds more like Dan oo... he isn't stable when it comes to walking he falls over every time were out down every road which gets annoying when have places to be and my 2 year old is walking with me and he's dragging his feet (my 2 year old refuses a buggy so she walks everywhere) and he's still wanting to nap mid day were as my 2 year old stays awake from around 8am to 8pm no problems, he's communication isn't great he will scream if he's getting told off and starts hitting himself.

I just don't know what to do anymore with the toilet training we have seemed advice from family, friends, health professionals and nursurys but no jou and have been doing this for the past 2 years and a half. Me and my partner we are exhausted and always stress when having to take him out or do our day to day lives.

With the new baby on the way we are now worried and stressing about the future with our 4 year old.

So I'm now seeking advice on here as I don't know who else to ask do you think he may have learning difficulties? Or is this normal?

Thanks in advance.

With the new