I'm cycle day 23, my cycles range anywhere from 30-38 days but am unsure of when I ovulate or when af is supposed to come. The last 2 days I've been SO tired and groggy and last night I started to get some lower back pain. This morning I woke up with really bad lower back pain and have been using a heating pad all morning 😥 For the last hour I've had a really uncomfortable pinching pain on the left side of my uterus. Af never feels like this and it seems too early, but I don't know what else it could be from. Could it be implantation??