In the hours and days following a horrific shooting like that one that took place this week in Parkland Florida, it’s easy to feel helpless. In the face of this kind of loss it’s easy to be gripped by fear and sorrow.

But moments like this also urge us to act. We do not have to accept this slaughter as the status quo. We do not have to let fear and sorrow dictate our response. We have the power to change this.

So often, people ask me “What can we do to stop this?” Here are three things you can do today — right now — to help stem the tide of gun violence in this country.

1. Join the Movement

There are organizations across the country that are working every single day to change our gun laws and make our communities safer from gun violence. They are targeting statehouses and local elections. They are getting measures put on the ballot for a vote. And they are organizing and urging Congress to take action.

Our movement is young — there’s no denying that the NRA and the gun lobby have had a big head start — but in the last five years we have seen its impact in a very real way. Local laws are changing. Voters are taking their message to the polls. And we are turning the tide in states and races across the country.

If you want to change our gun laws, the best thing you can do is find a group that speaks to you and get involved. Here are just a few of the amazing organizations working to fight gun violence in our communities:

Giffords, Mom’s Demand Action, Everytown for Gun Safety, Sandy Hook Promise, Newtown Action Alliance, The Brady Campaign, Coalition to Stop Gun Violence, Pride Fund to End Gun Violence and Connecticut Against Gun Violence.

2. Call your Legislators

Get a list of your state, local and federal lawmakers, call their office, and ask them where they stand on the issue of gun violence.

Are they committed to strengthening our background checks system? Do they support taking military-style assault weapons off our streets? How have they voted in the past on key measures to strengthen or weaken our gun laws?

As lawmakers, our job is to listen to our constituents. If our phones are ringing off the hook with people demanding to know where we stand on an issue — we pay attention.

Demand their attention. And promise to vote on these issues in November.

3. Commit for the Long Haul

On days like today, you will likely hear people saying “nothing will change.”

If it didn’t change after Newtown, or Aurora, or Orlando or Las Vegas, why is this moment different?

But I don’t feel that way. Creating deep and meaningful change in this country takes time. Years and sometimes decades. And every single one of these movements faced setbacks and opposition.

People said “nothing will change” before the Montgomery bus boycott.

People said “nothing will change” before Stonewall.

Change happens, if at the moment when it seems most unlikely, you decide to do more.

Today is the day you decide to do more.