Hi
I remember feeling exactly the same, that I was sure I had missed some vital things!
Along with the tea tree oil that Lisa recommends I would also buy lavender oil for the bath.. put 2 drops of each in a bath - it helps to heal your bits (milk them in a about 10mls of milk otherwise they will evaporate with the heat of the water).
Maternity pads - I found Always Ultra Night pads much more comfy than any of the maternity pads I'd bought.
I didn't try disposable pants but my SIL who had a C-section advised me to get some BIG pants just in case I had a section to avoid the pants going over the scar. I bought some really cheap ones from Primark (£3 for 5 pairs) but thankfully I didn't need to use them.
If you're planning on breastfeeding I would definately buy Lansinoh cream, it is amazing stuff and will heal your nipples if you get the latch wrong in the early days.
I didn't buy enough blankets and found that Olivia slept much better if she was swaddles so DH had to go out and get some more (the first few days at home she was sick a lot and the washing machine couldn't keep up!) Oh that reminds me, stock up on kitchen cupboard essentials so that DH only has to go to a corner shop for stuff rather than trecking to a supermarket!
A great tip my MW gave me about scratch mitts was to not waste my money but use socks instead! They go much further up the arm and stay on unlike mitts.
I also thorougly recommend going to the hairdresser sometime in the weeks leading upto your due date, I went the wk before and am so glad I did and meant that even if you could put your shopping in my under eye bags at least my barnet looked nice
Hope this helps
Lucy