Hi Rooey
Your syncope is probably due to your low blood pressure. Heavy physical work increases your need for oxygen. If your blood pressure is low then your body may only be getting the minimum amount of oxygen and when you increase your activity this increase in demand for oxygen could cause you to faint.
The cramps could be a number of things but I would suspect that they are Braxton Hicks. Most of the books will tell you that Braxton Hicks are not painful. However for some women they can be and are quite painful. If the cramps are irregular in length (one cramp may last for only a few seconds but others may last for a couple of minutes) and irregular if frequency (some may have only a few minutes between each cramp but there also may be many hours between each cramp) then it is Braxton Hicks. Other causes are stretching of your ligaments, baby moving or early labour.
Keeping up your fluids is a good idea. I would suggest that you should be drinking somewhere around 3 litres a day. Also make sure that you are eating enough.
If you have any more concerns feel free to contact me. Just be aware that at the moment I have a woman in early labour so it may take a little while for me to answer you