Breeze,
i have 2 children a girl (15) & a boy (

& 2 more different pregancies & births (different in every way, cravings or none, kicking or not!! - my son was very lazy!!, nausea or not etc etc no contractions at all for him & wham bam i'm here for her) would be hard to find. My point is that what you experienced last time may be nothing like what you experience this time.
You do seem to be very stressed (i suspect this is made worse by having to chase after a toddler!!!!) & this could be the cause of your pains. Tylenol shouldn't hurt either you or the baby but only use it if the pain is bad enough, otherwise it won't be any use if you suffer bad pain later, personally, i'd try trying to get some rest (is there anyone who can care for your son for a couple of hours a day?) because if this is caused by stress/worry then rest may be the best cure.