19 mth old Normal or more too it ?

[Dilligaf81]

DD 3 is 19 months old and 'challenging'.

My other 3 children were really well behaved never had a tantrum whereas DD3 throws herself on the floor screaming kicking out etc and she can go for ages. I usually take a few steps away then watch her without saying anything (not giving her any attention for her bad behaviour) I have been known to be standing there for 20 mins.
She drinks lots of water (compared to what the other 3 did), she isnt particulary bothered by food but does sleep well at night (7pm - 7:30am).

I just dont know if she is frustrated that she isnt doing what the older 3 are - they are 7,5 and 4. She walked at 9 moths and is talking in short sentances (mum and dad go to work, Look at the doggy etc) and her ability needs to catch up with her mind IYKWIM

OR

Could it be other issues - someone suggested Diabetes but does that affect behaviour ?

I just feel like a real failure, I thought I have this parenting thing sorted and DD seems to want to prove me wrong.

Sorry for the rambling.

Have a read of the challenging child by Stanley greenspan. It helped me a lot with ds3 who sounds similarly stubborn.

She sounds really normal OP. DS2 can tantrum for even longer, 35mins under the dining table was hit record I think. Sometimes I don't even know what they are about! DS1 didn't really tantrum like that so it was a bit of a shock for me too. You're doing the right thing, just be visible to her, every now and again say "cuddle?", but obviously don't give in to demands.

Undiagnosed diabetes would affect behaviour. Maybe get her tested then you can hopefully rule it out?

Thanks Ill get that book, I think Ill go to the dr's anyway just to rule it out.

Then I can realise it's just down to me and not anything else.