suz,
Adverse reactions are common to pain medications after surgery. Lower blood pressure isn't an issue after surgery unless it is causing you symptoms such as fatigue or light headedness.
Your pulse is on the upper end of normal but that also could be due to the recovery of your conditioning.
I would continue with your cardiac rehabilitation, if things continue to improve then I wouldn't worry too much. If the nausea or other symptoms persist you might consider further investigation or a peptic regimen with your primary physician.
good luck.