Only one week after Sean Lowe and Catherine Giudici announced their engagement to the world on The Bachelor, Life & Style can exclusively reveal that the couple were caught having a major public fight at an LA hot spot — and again two nights later on the way back to their separate units in their apartment complex.

To celebrate his first performance on Dancing With the Stars, Sean and Catherine hit The Sayers Club in LA on March 18, but eyewitnesses tell Life & Style their romance seemed to be over.

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“About an hour after they arrived, Sean and Catherine were in a corner, and she was clearly mad at him, yelling at him,” an eyewitness dishes to the new issue of Life & Style. “Sean was trying to talk to her, but she didn’t want to hear it. She was fed up with him and rolled her eyes. Then she started crying, wiping her eyes and looking away from him.”

The partygoer tells Life & Style that the argument lasted for 30 minutes, adding, “She was shaking her head and hands at him.”

Even before their big blowup at The Sayers Club, a second eyewitness tells Life & Style there was a “chill” between the couple earlier in the evening at the DWTS afterparty at Planet Dailies.

“They sat side by side at a table at the back of the restaurant with some friends, but they hardly talked,” shares the party guest. “Catherine was texting on her iPhone while Sean was drinking beer and toasting with his buddies that he had flown in from Dallas. He was being very goofy, very frat boyish, and Catherine looked like she didn’t want to be there.”

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Two nights later, the couple were spotted arguing again while walking back to their apartment complex. “I could hear Catherine talking to Sean, and she sounded annoyed,” reveals a source. “They were having a disagreement about something. I heard Catherine say, ‘That is annoying, Sean. Why do you say that?’ Sean was trying to calm her down.”

For more inside Sean and Catherine’s first weeks as a public couple, pick up this week’s issue of Life & Style, on newsstands now!