You're expressions of obvious disgust over women's periods is worse than a few 'rude' comments.
And yes, you do have a phobia.
Even now you equated a woman simply mentioning that's she's on her period with a man saying he's going to do a 'big' poo.
Tell me how those expressions are even similar?
Earlier you said a women simply telling you her period has arrived made you think about her actual vagina and made you feel queasy and it was inappropriate therefore to mention. That is not normal. Why on earth would you think about another woman's actual vagina?
You may have thought such thoughts and reactions were normal before, but now are being told that it's unusual. Outside the norm. Because it is.
I have a phobia of heights. I feel queasy and dizzy in high places and can barely stand on a balcony. Went to a water slide in a park in Florida and had to push against a crowd of people to get off the stairway as I couldn't hack it. I know I have a phobia and I know my thinking is irrational and I own that.
I do not think others shouldn't mention their travels to mountain peaks or high places or think they're disgusting. Mentioning those things does not give me a negative feeling.
No one announces they're 'going to poo' (large or otherwise) and a woman doesn't say she is going to 'bleed'. They say they need to use the bathroom/lav or they're on their period. Anyone who finds the utterance of either phrase upsetting in metropolitan life is greatly over analysing it, deliberately framing it in a negative way and frankly showing a lack of control over their thinking.
Neither phrase is graphic in any way. Neither has connotations of misogyny in quite the same way as being 'upset' at the mere thought of a woman's normal bodily functions does either.
Sadly they'll always be a time when due to periods arriving early or endometriosis or PCOS or period poverty or some other issue a woman might have to confide that she needs help or support in dealing with it (borrow a pad, a trip to the shops to buy replacement knickers, time to use the bathroom, or buy pain meds) and how dreadful that they might avoid confiding in a man, but choose a woman, and that woman, who menstruates herself, gets the ick and finds it upsetting and finds it inappropriate that they even mentioned it.