Rather is spot on Yorkshire. I myself felt like I was behind schedule however it's not a good way to look at things. We're learning to do something and there is no prescribed rate at which we learn (especially when there are so many other factors that have an impact on what we are able to do).
In my case, I decided to focus on what I could learn about what held me up to try to minimise the chance of it happening again and reduce the impact should it happen again.
I'd also like to point out what a monster sized bit of crazy you are for putting yourself back into it at week4!!!!
I mean, come on, anyone other than the likes of Paula Radcliffe would balk at that!
Don't be so hard on your body!
Week 3 sounds a much more appropriate place to begin (even if you just opt to do one run from it and then move on).
Don't be downhearted Yorkshire, you're my double 'ard lady who runs AND pushes two children around
and long may you continue to be!!
When you go out next, good warm up, go slow (preferably sans enfants), lovely hot bath to soak in and one of these babies 
should you feel the need. We'll get there!!
Rather - when I read your list I find myself thinking 'I do that too' (except the spitting, I just can't do it). Hope you're not spying on me. (Actually you can't be as you've made no mention of 'When my trackies randomly start to fall down, I save my 
es by undoing my hair, using the bobble to tighten my trousers and then try to knot my hair without stopping my shuffle!).
Skip - Welcome, welcome. Cheap trainers are fine but whether they are fine for you will depend on how you run. If after a few runs you find you've got pains in your feet it may well turn out that you're not getting the support that you need from them but you'll only find that out by running.
Good luck with it!