Hello experts! Please help

Period due today. Normally get a twinge(s) two days prior indicating the impending arrival, did not get any.

When I hold this close to natural light I think I see something

Not in the first pic. But in the 2nd two with natural light. Do you see anything??

Any advice?

Can anyone do a reversal/negative type of color on one of the photos?? (2nd or 3rd)?

Or tell me how to do it!