7 week old baby weighs 13.4lbs. His birthweight was 9.2lbs. Everything else is fine. Should I be worried he is eating too much?

No. A rise of 4 lbs in 7 weeks is fine, as weight can fluctuate at that age. Try and stick with about 24 ounces in 24 hours and you should be fine. Make sure to keep regular dr. appointments with regular height and weight checks. Best wishes.
Depends on length. Ask your pediatrician on the next well baby visit coming up. This should not be a problem once he weighs and measures the baby and the baby length, especially if the baby's eating and sleeping well. He may be in a rapid growth phase.