I'm lost, worried, excited...

Anyway 2 weeks ago at 27 weeks appt I had an ultrasound done and everything is great besides she seen that where the cord and placenta meet its not in the correct place.. she said that it could potentially not let him grow efficiently... otherwise he measured 2.5lbs at that time. Everything else is good. Then at my 29 week appt (regular visit) I had gain 4lbs in 2 weeks and my belly measured at 32.5/33 weeks by the tape thing... now I'm totally confused and lost as to what's really going on. This is my 3rd baby... first born at 33 weeks (pre-e) 2nd born at 38w5d (repeat c-section)... I will have another regular visit the 1st and then another ultrasound on the 15th... I feel every movement twist and turn, kick and punch, what happens if he runs outta room?