Was it possible to organize a women's uprising or feminist movement in the Middle Ages?

No, it was not possible

• Equality in this world was a concept completely alien to Middle Ages. In those times people were sharply divided between social strata (monarchs, nobility, clergy, peasants, city dwellers etc ...) There was very little chance for social mobility (for example for peasant to became noble) . Society was held together by religion which claimed that everybody should accept his or her role on this earth (for reward in Heaven) , and not seek to be something that he or she is not. Equality in this world was replaced by transcendental equality before God. Therefore, idea that men and women should be somehow equal in medieval society would be completely alien, just like idea that king and peasant should be equal.

• Women make poor soldiers. Chance of female army defeating male army are minuscule even in this day of technology. Being a solider simply requires lot of physical strength and endurance, and average female is much weaker then average male, plus has less testosterone to influence aggression. Going back to Middle Ages and time of spears, swords, bows and heavy shields and armor, chance of having successful female-only army were nil.

• People do not associate by gender. Women have some male person in their life that they hold dear, and vice versa. Sons, brothers, husbands, fathers, relatives, or simply friends and neighbors, people you do not want to wage war against. Most mothers would not go against their sons to establish some fictional matriarchy for women they do not know or care about, and most sons would not go against their mothers to defend some fictional patriarchy .

Gender inequality is a completely unproven concept. It's more a modern fantasy, not much different from how the Victorians looked at the middle ages ('Ivanhoe'). Very much like walking along the buffet and picking things you like, and ignoring the things that don't confirm the concept.

Until about a century ago most of both men and women led a tough life. Both partners had to struggle together to make ends meet. Very few women simply had the time to wonder about equality while churning the butter, doing house work and taking care of the kids. Their husbands would toil equally hard in whatever profession they had. They had no time for quibbling over perceived injustices; not starving to death takes precedence.

Apart from that, feeling unequal isn't something you worry about if you don't have the right to vote, which most people until 1900 didn't have to begin with. It's not a coincidence suffragettes were upper and higher-middle class women. They had the time and the means to worry about voting.

Feminism is a fairly modern concept, not much older than a century. You're looking at history with your modern viewpoints. That rarely works. The current feminist ideology in practice (extreme equality, male patriarchy oppression, etc.) is not even a decade old.

Concepts of prosecuting a people’s gender war for matriarchy are modern (post-Enlightenment) fantasies or farces of the reversal of modern gender roles. Correspondingly feminism and rights are both also modern social relationships.

Medieval women did seek to change their position in the social system. Amongst the second estate nunneries were not simply holding cells for unmarriagable females, but were vast women controlled economic institutions that owned lands.

In common beguines conducted urban trades and ran autonomous women’s houses.

Women were most economically effective for the patriarchal household when they were independently capable of running it. Women kept manor and castle oppressing peasants while their husbands were at war. They themselves received war in siege.

Urban women often married a husband in trade who was twenty years older, then as he died married a husband in trade twenty years younger. The real theological question about “which wife in heaven” shows how deeply this marriage practice worked.

Peasant women were effective brutalisers of the patriarchal household. They exerted power and control.

Women didn’t form a class conscious revolt because they were not a unified class: they were divided by differential production relations.

Women did not form a matriarchal ideology because they were beneficiaries of the patriarchal economic household. They could both modify existing patriarchal relations (got him by the balls) or act as the patriarch (old Lady Macbeth).

The extensive literature portraying nunneries as brothels, and that Everyman was a cuckold indicate that women didn’t experience a substantive limit on sexual expression. The formal limits were identical to the formal economic limits, as above.