cluster feeding 24/7

My lo is going to be 4 weeks tomorrow. For the last couple days she wants to eat 24/7 and the boob is the only thing that calms her down and stops the crying. She is absolutely eating enough - she gained 1.5 lbs in 2 weeks. I do think she has gas though and she isn't getting enough sleep. She has gotten two large stretches of sleep totaling 7 hours (3.5 each) in the last 24 hours and all other sleep has been in 20 min to 45 min incraments. I would guess her sleep has been more like 12 hours in the last 24. To top it off, she starts crying the second we lay her down in the rock and play, so all of those cat naps have been on my chest. She is definitely asking for food every half hour to hour when she is awake. Help! Does this seem like a phase or do you think something is wrong?