PMS or pregnant? Help please!

I’ve been getting getting a achy sore lower back, I feel tired and don’t seem to have much energy.. my back hurts more when I wake up and I’ve woken up today with very slight pain on my left side.. is this pms or a sign of pregnancy?

I’ve only been off the pill two months so unsure what my cycle length should be.. my period came on cycle day 42 last month and I’m currently on cycle day 31..

Last night I wiped to find what looked like egg white cervical mucas! I tested 11 days of flashing smiley on my opk last week but never got my peak as I gave up testing..

Advice please :)