First of all I think you should wait a while to see if it's what you actually do want - it's only been a couple of days after all, and you might realise in a week or two that you were just missing your old bun, and you prefer a life without furry commitments!
Do you still live with your mum then? As rabbits live for quite a few years you need to think about how they'll fit into your future - where you'll be living, how much time you can dedicate to them etc. For example, if you move out it'll probably be into rented accomadation won't it? Most landlords don't like tennants to bring pets.
If you definately decide you want another, and your situation and accomadation is suitable, how about a rescue?