Worried about my 15 month old DS development

Hi everyone,

I just have a few questions really and would value your thoughts and opinions, my HV is due to come out but not until the end of January. I'm a first time Mum who suffers from anxiety which has been made worse since the birth of my DS. My Son was born at 37 weeks and is due to turn 15 months next week, he is a big guy on the 95th percentile for both height and weight. I have concerns over the following things and any help would be great:

1. DS is not walking independently yet, has been pulling up since 8 months and cruising since 9 months. He crawls up the stairs. He walks great holding onto one finger but as soon as he lets go he just drops to floor and crawls (bum shuffles). Is this something to be worried about?
2. DS is not talking yet, sometimes we get the odd Mumum and Da dee but other than that there's just lots of babbling and squeals, grunts etc. Would this be classed as a delay? I'm so worried that he will never speak.
3. He started pointing to show last week but is using his whole hand, is this ok? and more to point if we ask where something is, does whole hand pointing precede index pointing.
4, He points using his index finger when looking at books and can point to lots of different pictures in books and knows items we are talking about.
5. Today he has starting picking up a brush and tries to brush my hair with it, is this normal or should he be trying to brush his own hair?
6. DS waves hi and bye bye but mainly if someone has waved at him first. He has only clapped properly once the rest of the time he claps one hand on the back of the other. He does bang two objects together.

I really just would like to know if you think this is normal behaviours or should I ask HV for a referral? I'm losing lots of sleep over this. He's a very smiley, happy, social baby.