If it's easy for you to get money on a poker site and you have no problem reloading if you go broke, then maybe give 5NL a shot and see how it goes. The important part is to be able to drop back down to 2NL if you're struggling rather than going broke, redepositing and trying again.

You don't have to start at 2NL to be successful at poker, but you do need to play within your bank roll. So either drop down to 2, or up your bank roll so you can play comfortably.