Turn that frown upside down!

Sad mommy Kourtney Kardashian was looking rather depressed as she headed to a friend's birthday party in Los Angeles on Friday afternoon.

The mom of three looked like she was still fuming over her latest argument with hubby Scott Disick. After being separated for weeks, the two reunited yesterday for lunch at King's Fish House at the Commons in Calabasas, Calif. Apparently things are not all well with the two -- because today it looks like someone rained on Kourt's parade!

Last week, the oldest Kardashian reportedly put her foot down and made Disick cancel a few of his UK club tour gigs. Instead, the Lord joined Kim Kardashian and Kanye West in Paris.

On March 5, the father of three was supposed to appear at club Switch in Southampton, UK but pulled out at the last minute. The club posted on its Facebook page, “Due to circumstances beyond control of both the club and the organizers of tonight’s event, Lowercase Events, Scott Disick will be unable to appear in Bournemouth tonight, having decided at the last minute today to travel to Paris, instead of meeting his contractual obligations to attend nightclubs in both Southampton and Bournemouth.”

In addition, the LD was scheduled to appear at Tiger Tiger in Croydon, England -- but bailed at the last minute. The venue tweeted, “The Lord has let us down.”

Looks like he's letting his lady love down too ...