I woke up with a pounding headache after working the late shift in Washington DC on Inauguration Day. It was a hangover from covering the inaugural balls, but not from booze.

It sounds like a glamorous assignment, watching the new President celebrate, thank supporters and take a spin with his wife on the dance floor for the first time as "First Couple".

Unfortunately, we were reporting from a live position outside the hall in a cold mist, far from the Washington elite.

Drinking water is a liability when you're a reporter tied to a camera in situations like this where relieving oneself involves a long walk to find a bathroom, in a ball gown no less.

Dehydration, the fact that more than 24 hours had passed since my last cup of coffee, and a general sense of uncertainty over the direction of the country were all no doubt taking a toll on my head.

I thought I should try to catch an earlier train home to see my kids and send home my sitter.

Outside my hotel window was grey and wet but the street was awash in pink knit hats and people, mostly women but not only, some carrying signs, others wearing sashes. My hotel was just blocks away from the US Capitol Building where people were already starting to gather for the Women's March.

As I pulled on my jeans and packed up my things I could hear the buzz of people below. I knew official estimates for the crowd were huge. I felt I couldn't leave the city without taking a look. I left my bags with the bellman, telling him I'd be back in 20 minutes.

It ended up being an hour or two. I went out in the street to take pictures of the signs and saw a huge crowd a block away moving toward the Capitol.

"Thou shalt not mess with women's reproductive rights," read one sign citing a verse from 'Fallopians' as if a sexual organ were a book of the Bible. A few photos gave way to some videos, as I tried to capture the giddy mood and sheer volume of people I was seeing.

Staggering numbers

The numbers seemed staggering. As I walked up Jersey Avenue and right toward the capitol's big white dome, I asked people where they were from.

"Colorado," said the first group of white middle-aged women I chatted with. At the corner I ran into a younger crowd from Maryland and Boston and mothers with daughters from Chicago, Virginia, California, Minnesota. There were men and children too.

Their signs touched on marchers' many concerns under a Donald Trump presidency, from immigrant rights to disability rights. The focus of organisers and the majority of signs, however, was women's reproductive rights.

The crowd was mostly white, but diverse, and it was minority women who took the lead in organising: Tamika Mallory, Carmen Perez and Linda Sarsour, and African, Hispanic, and Muslim American respectively.

White feminist icons were also on hand, like Gloria Steinem and the pop singer Madonna (Cher tried to come but got stuck in traffic). And there were men too, such as filmmaker Michael Moore.

I've reported on a fair number of demonstrations in my day, from Ferguson to the streets of New York, but I could tell this was big. Even by DC standards. As I finally made my way towards coffee and the train station, I was feeling better. I spent the three-hour train ride back to New York monitoring news sources and social media.

Protesters were forming huge crowds in Chicago and San Francisco as well. London was having a march too! Every state of the union, every continent of the world was taking part. Now we know from experts that more than a half million people attended the DC march; worldwide it's estimated that more than three million took part.

'You lost'

I saw Trump supporters on social media dismiss the action as sour grapes: you lost, get over it, they posted.

Some focused on the violent confrontations between police and protesters the day before that resulted in a couple of hundred arrests. One Facebook friend saw my photos of the march and asked how women’s rights were being threatened by Trump.

Here are a few facts: one of the first things President Trump has promised to do is appoint a conservative judge to the Supreme Court.

While most experts don't believe the court is likely to overturn Roe versus Wade, the decision legalising abortion, in the near future, a right leaning court is likely to allow states to enact more restrictions, making access to abortion more difficult. Repealing Obamacare will most likely mean no more free access to birth control for women.

Republicans have also promised to cut funding for Planned Parenthood, which they despise because it provides abortion services, primarily to low-income women, in addition to reproductive health care, like contraception and screenings for sexually transmitted diseases as well as cancer.

Interestingly, some anti-abortion groups wanted to march as well, but complained about being left out by organisers.

I was still glued to social media after I jumped in a cab back home in New York. But as we made our way slowly through midtown traffic, the distant sound of beating drums caused me to look up.

A march was happening here too. Many neighbours and mothers from my children's school were posting photos of themselves there, people I had never seen taking part in demonstrations.

The question many were asking was telling: "How do we continue this movement?"