I just bought a ticket with Ryanair from London to Cork but I didn't select the option to add a checked bag. I was stupid and I assumed the bags they allowed to be taken in cabin would be similar to other airlines and I assumed my backpack(for backpacking) would be safe. Upon further research I found that the tallest something can be is 55cm. I am very concerned since I do not have 60 euros to throw around in the case it doesn't meet their requirement. Fellow backpackers, what have you done and what would you suggest I do?