I thought that HTTPS meant that I could trust the security of a site but I've noticed that my email account for example doesn't have the padlock - it has the i icon instead so I'm confused as I thought that this meant not secure. I'd be so grateful if someone could explain this to me!!!
HTTPS does mean it is secure, between your browser and the server. You don't need a padlock to be showing. Are you getting certificate errors of any sort? Your browser will make you aware if the channel is being tampered with. Now, you must understand, if you are using an unsecure wireless signal, then it doesn't matter if the server is secure or not, because your neighbor is sniffing your traffic!