Kerri
With SPD its unlikely that you will 'only' get pain during the night. You don't say where the pain is exactly but it is very common to get lower back and/or hip pain during the night due to the relaxation of the pelvis making it harder for your body to cope with the extra weight. However pain on turning over and getting in and out of bed is 'one' of the symptoms of spd.
The Pelvic Partnership website is a good source of info and is run by women who have all experienced spd themselves:
here
I had spd in both my previous pregnancies and it has begun to rear its head again in this one although later than it did in the others (am nearly 22 wks).
I had little or no support from the NHS for spd during either previous pregnancy despite them being in different health authorities.
I would definitely mention it to your midwife though, as if you do have it, some areas will arrange for physiotherapy and a maternity belt and the sooner you seek treatment the better.
Personally, I tried to prevent it this time by seeing an osteopath to make sure my alignment was ok and buying myself some MBT trainers and walking daily to build up my pelvic and lower back strength before I conceived. It seems to have helped, as although I have started to have symptoms they are nowhere near as bad, or as early, as previous pregnancies, so I am keeping my fingers crossed.