Difference between SPD pain and Labour???

[pookie81]

This might sound silly but I am 38 weeks pregnant and have been suffering from pains down below as well as bad back pain..and tightening sometimes I wake up in the night thinking "this could be it" but will I be able to tell the difference between the two? I sometimes sit up in a lot of pain around my abdomen also. Help! :-)

This sounds more like Braxton Hicks (practice contractions) than SPD. Trust me you'll know when it's the real thing cos the pains are totally different.
If they're coming very regularly and the time between them is regular too, then it may be contractions. If in doubt, phone your MW or birthing unit.
My MW said if you can hold a conversation while having the pain, it ain't a contraction

BH's can be quite painful, but I agree with Iklboo, you WILL know when they are serious contractions...no doubts at all!
Good luck...get lots of rest...