I had three, donated for ten more last night
I'm now at ten
Is my display wrong or did I lose three fp somewhere?

You had three and donated for 7 last night, not 10.
I think the confusion comes from the fact that you probably wanted to donate in €, but donated in $ instead, so 19$ and not 19€. (We are not even sure how that worked as the donation system should not let you donate amounts that don't fully add up to Fairy Coins. So that should not be posible and also has never happened before). 19€ would be 10 Fairy Coins, but 19$ are 7,6 Fairy Coins and since we don't round numbers that's 7 Fairy Coins.

When I donate, I specifically list ten points and have PayPal convert the currency on my end
Have since I found that donating in dollars means more fees on your end
So yes, I should be at thirteen
Now I wonder if that's PayPal messing up or something else somewhere

Please check your PayPal account. All the information about how much money was taken from your account can be found there.
19 US$ were transferred to us, not 19€.

I am sorry about this, but this is not something that happened on our end and probably a PayPal issue that is out of our control. You should not be able to donate odd numbers for Fairy Coins and as said, this has never happpened before. Starkad looked into it already and says he has no idea how that could have happened from our side. We have not changed anything on our end. I know Paypal is currently undergoing some changes, but I am not sure it has anything to do with that.

I can reverse the transaction and refund you all the money of the transaction and remove the Fairy Coins /queen gift from your accont again if this is what you want.

I'll keep the FP, I intended to donate as it was
Hopefully it won't happen again, to anyone

Argh! It seems to be a new issue with PayPal. Today we got a donation in British pounds.