Momsh, please see your OB agad, back pain + swelling + exhaustion at 34 weeks needs checking talaga, hindi ito basta normal pregnancy discomfort. I know it's scary thinking about early birth, especially with your toddler and bills to worry about, pero the doctor needs to rule out anything serious para sa baby at sa'yo.
One of my mum friends had similar symptoms and her OB just adjusted her activities, rest more, less standing, and it helped so much. What you're feeling is real, and you deserve proper monitoring, not guessing lang. Kaya mo ito, and your baby will come when he's ready (and yes, sometimes earlier than 40 weeks happens with second pregnancies!). But please don't wait, book that appointment today, okay?