From someone who has NEVER had a break in the time i've been a mother, if the offer is there and you feel comfortable, i'd consider it! Everyone needs some time to themselves every now and again. It is so tiring being a mum and on demand feeding too.You sound like you need some rest.
If you are not making a regular thing of giving formula, it shouldn't matter, or affect your supply too much. You may feel a bit full and slightly painful so expressing may be a good thing,
I've never managed to give Angel a bottle no matter how much i tried but there's no saying you LO won't take it.