Two questions:
1) Is it possible to log into your wallet from any computer using the electrum software and your seed? For example .. if you went on holiday or your computer broke?
Yes but it's not an email account it's a bitcoin wallet. Money is at stake and because bitcoin transactions are irreversible there is nothing that can be done if your coins are stolen. If you expose your seed on a public computer or a compromised computer then your funds will be stolen. So use your own devices only. And understand that the more devices you use your seed on the greater the likelihood of theft.
You have to use electrum.