My husband, who doesn’t have PD, had a similar experience with passing out suddenly with no warning or the other issues you had with sweating,etc. our pcp sent him to a cardiologist and after 4 weeks on a heart monitor he will receive a pacemaker on Thursday. It is important that you follow through until you get a definite answer.
🌈TheaD

Low Blood Pressure comes with Parkinsons. It is called "Postural Hypotension and Orthostatic Hypotension. Drink plenty of water, make sure you eat a balanced diet with fiber, try not to change positions quickly, try to avoid bending over, take care when getting out of bed, salt, consider raising the bed 15cm., avoid caffeinated drinks at night, eat small frequent meals, and finally, avoid sitting or standing still for a long time. Parkinsons.org.uk Managing low blood pressure and Parkinson's. Linda237

Hi! I have always had very low blood pressure, and never did enjoy drinking water. But as I got older I found myself in the emergency room on several occasions because of dehydration. One time the nurse told me that my blood vessels were starting to collapse, and that they didn't know if I would make it. It took them almost 24 hours to rehydrate me. I had all the symptoms you described, especially the nausea and vomiting, plus hallucinations one time. Now I fill an 80-ounce pitcher full of water every morning and just keep refilling my water glass throughout the day until it's all gone. I've learned to enjoy the taste of water, especially with ice.😊

Try extra fluids and even a little something salty.

My husband has PD and has episodes of post-exercise low blood pressure, aka host exercise hypotension