Update:
I've managed to send now. The reason the "suggested fee" was wrong is my own fault, when I first installed Electrum I modified the transaction fee setting under preferences (before I knew anything about it) and set it too low.
Now I have a further total-noob question. This was the first time ever I sent any BTC, so far, I only received, from a multipool I mine at. I just made two transactions. One was a donation to a guy who runs a cool stats site. The other one was to myself. What I did was sent a tiny amount (just over 0.01 BTC) from one address, to another address of mine which contains the bulk of my balance. I wanted to "consolidate" my balance, which was split between three addresses. After I did this, the address that I sent from disappeared out of my list of addresses in Electrum (and I think another new address got automatically created to replace it). This is where I'm confused. I read on BTC wiki that BTC addresses are one-time-use only, and it literally says: "Unlike postal or email addresses, Bitcoin addresses are single-use.
This means that whenever you want to receive a payment, you need to generate a new address.". I don't understand this, as I'm using one address on this multipool, and I'm receiving payments to that address every day.
So what I'm wondering is, now that the address I transferred the entire balance from has disappeared, what's "happened" to it? And also, what would happen if anyone ever tried to pay me to that address? Would the payment "bounce"? Or just vanish, and neither the payer nor myself would have it?
Sorry for the noobness of these questions...
Thanks.