An au pair is not necessarily a lot of money - but could be a life saver for you.
There can be different numbers of hours they work, so if you are happy with nursery, the AP can bring them some mornings giving you some leeway to get away, and can do collections some evenings for you. She could have the house clean, and do dinner a couple of nights a week. If illness comes up, she could do the main cover in the day, with you organising all in the morning, going to work and popping back at lunch, and she just minding for afternoon.
We used to have an AP doing 20 hours (they can do 15 up to 40, depending on what you need - different levels of pocket money payable and usually number of hours agreed before arrival) and DD stayed in school/afterschool club but got home earlier a few afternoons to play with friends, and APs we had mostly did cleaning rather than cooking, but some cooked one night a week.
It was an intrusion into personal space at home, I really did appreciate that back when the last left - but it really did help at a time when we needed it. And all APs we had did language classes a couple of nights per week, which meant they also made friends and realistically, mostly spent every night and most weekends out once DH or I got home to take over.
If AP is really not an option (the only space they need is a decent bedroom of their own - we don't have ensuites for ourselves let alone AP!), do try to find a nanny or minder who can do evening collections for you - even if it's only 1 evening a week, that can take the pressure off you. We have now found a lady who collects DCs from local schools to bring to the afterschool club (doesn't stay in afterschool club, just drives the DCs there), who is very happy to do 1 hour in the mornings in our house to supervise DD (getting up, breakfast and out to school - realistically it's only breakfast and school) 4 days a week, and that is working well.