When is a mum ever a Part - timer

Man, what a busy week. Monday is mayhem at the moment and Tuesdays are busy....and by Wednesday morning, I want to know "Is it Friday yet?" (Mind you Friday does not mean that I have time off.)
When I first rejoined YWAM I thought that I would make things easy and say that I am part time in mission, rather than a full time ministry. The truth is however when is a Christian ever part time in what we do?
At the time of writing, it is only a few weeks until I am off to Germany. This week I was in Stirling doing Street pastors, Arbroath on Tuesday with money management and Thursday in Aberdeen with a staff day. That was my "work" or ministry.
I also work with the Scottish Society for Autism, for what I see as a "tentmaking" ministry to support my YWAM work and this week I have done that each day not doing YWAM or ministry stuff.
I must admit, I am tired, very tired.
The dilemma that I find myself in however is this:
If I turn down shifts (and I did turn down some anyway) would I be saying "No" to God's way of providing the money I need for Germany?

I believe wholeheartedly that God wants me to go and do the DNA Infusion conference. So if I turn down the shifts in the next few weeks, what happens if the money I need to go does not come through.
Would I be a bit like the guy in the joke that asks God when he reaches heaven why did you not help me God in the flood. And God answers I sent a boat and a helicopter and you said no to them. (Paraphrased version)
So yes it is true to say I am working far more than I would like to at the moment....but even when I am off....I am a mum and a wife - so when is the day off exactly?

Even if it is my day off if an opportunity arises to share what God has done or is doing I am not necessarily going to say, come back to me next Thursday. (Although sometimes those boundaries are easier set.)

At the moment I hope that I won't burn out so much that I am too shattered to participate and gain from what God has for me in Germany.
As a mum though, I am still dreading being away for 3 weeks.