Early labor signs at 39+5???

I haven’t worked in 3 weeks at my job as a server. I decided to today and it was an 8 hour long shift and I was a bit sore but really didn’t feel too bad. Since I left work my back was starting to ache a little. Now it’s been 5 hours and my moreso middle back is hurting pretty constant. Sitting or standing and I’m feeling pretty crampy. No noticeable contractions. It’s more of a constant thing that lays off once in a while. I did have some light pink discharge when I wiped. Is this an early labor sign or is this just from me working????