the answer is 'eat and lift'. so basically you're on the right track.
what are your priorities? Do you feel like you value running, lifting, and rugby all equally, or is one more important than the other 2? How good do you want to be at any of these? The only problem that I can personally see is that by chasing these 3 goals, you won't end up great at any of them. Or in other words, you will truly limit your potential lifting-wise if you keep running cross country. Unless you're an absolute freak athlete, specialization becomes important at some point. That point will probably be when you stop seeing progress in either your running or in the gym.
You don't necessarily need to answer these questions on here. They are just things to think about