Feeling unwell before labor begins?

I don't feel well suddenly. I'm neasous and just feel off. Ive taken tums to help bc usually my heartburn causes it but it hasn't helped, don't have an appetite and just feel like run down.. baby is moving non stop and super low so it's painful.. it's also a tightening feeling sometimes, but can't tell if it's just the baby or a mild contraction. Is it common to feel unwell before labor begins? Also keep having the urge to pee and go number 2.. ugh just done due date is in 3 days.