Back pain 7 days before AF

Meghan
I would appreciate any tips or advice on my following symptoms. Been TTC for 3 months. We used an OPK this month to ensure we did our BD on the right nights. I am 5-7 days before AF arrives. Having lower back pain, sore breasts and feel tired. Any thoughts?  Hoping it's not AF and feel very anxious about it. Thank you all!