Rep. Alexandria Ocasio-Cortez (D-NY) comforted fellow Bernie Sanders supporters after a string of losses Tuesday night and warned them not to let their hearts “turn black” as the candidate’s chances for the nomination slip away.

Ocasio-Cortez participated in an Instagram live Q&A on Tuesday and offered advice to fellow progressives reeling over Sen. Sanders’ (I-VT) big loss in Michigan’s primary vote.

“There’s no sugarcoating it. Tonight’s a tough night. Tonight’s a tough night for the movement overall,” she said, clarifying that it is tough “electorally” but suggesting that there are lessons to be learned from the experience.

The lawmaker highlighted the “generational divide” in the results, noting that older voters have “decisively” backed former Vice President Joe Biden.

“First of all, if you win a race, you win a race, and I congratulate Vice President Biden,” she said.

She stressed the importance of understanding the developments in the race, telling fellow progressives that they can use the information as a tool and “deconstruct it and then reverse engineer and develop a plan to win over and over again.”

Ocasio-Cortez also said that those who are fighting for a “progressive future” and “everyday people” must keep their heads up, because some people “want you to be demoralized and “don’t want you to vote.”

“It has been my opinion and it will always be my opinion that the number one enemy that anybody has, especially this movement and our movement has in politics, is cynicism. It’s not any one person. It’s not any one actor. It is how we show up every day,” she continued.

“And I think it’s important that if you’re feeling sad, you’re feeling down, let yourself feel that way. But the number one rule in politics my opinion on organizing, in general, is to never ever ever ever let your heart turn black,” she said.

“You can’t do it,” she added. “We cannot afford to do that. There are too many people’s hearts who are on the line.”

Sanders lost the night’s biggest prize, Michigan, as well as Mississippi, Missouri, and Idaho. North Dakota and Washington were not called at the time of this writing.

The losses follow a disappointing Super Tuesday for Sanders, with his opponent Biden successfully sweeping the south and taking the lead in pledged delegate totals.