I'm with ironraven on this one. It would be smart to carry at least a couple of days worth of high energy food so you can eat while you build a camp, gather wood, set snares, etc.

The most important number one ultra important thing (even more than food) is water! You can't carry 30 days of water so you need to be able to get your own and purify it. A good filter would be recommended as you'd need a lot of tablets to clean this much water...but for this duration boiling would be best as it's hard to run out of fire...save the tablets for the slim chance you do run out of fire. In your example you're near water but if you weren't you'd need to be able to store as much water as possible.

Other than water, sanitation is next important IMO. If you want to stay healthy, you need to keep yourself clean, keep your area clean, and dispose of your waste in a safe and clean way. If you're fed, you're going to poop!