1 Pregnancy Test left... HELP!

Hi team,

I am on cycle day 51 and I have 1 test left and want to use it wisely!

Last couple days iv had sharp stabbing pain on right side and sorest back pain with little bit sensitivity/ itchy nips nothing major tho and this morning a headache behind my left eye.

Please let me know if this is implantation I took a ovulation strip and was really light colour so I don’t think I’m ovulating.

OR

Am I just having symptoms and my body is just out of whack since of the long cycle.

Please help!