I set up a forum the other day and I did not get a activation email. I checked both inbox and spam and it was nowhere to be found. Do I need to set up a new forum or can the email be resent?

Some email providers block Forumotion, so you need to add it to your list.

But I have received 2 other emails from here

So what are those 2 emails about?

I think you need to wait a bit. My confirmation email took a while but it arrived.
Content Removed ~ Member Banned ~ MrMario

These emails were a welcome to the forum and a watching topic email.

Should I try to set up a new forum again?

There should be links in those two emails that will take you to your forum.

I had a link to click on in one of tehm but it was invalid.

I got this message:
The activation key you supplied does not match any in the database.

Maybe I am misunderstanding what you are asking about. Are you saying that your login information is not correct or you can not remember the forum's url/address?