Lindsay And Sam Split Again?!

But how can they split up if they never officially got back together? And what about all those nights Lindsay slept over at Samantha's Hollywood pad? And what is Lindsay trying to say with these cryptic tweets!? Ugh, so many questions! Last night, Lindsay posted the following messages on her official Twitter page, and it appears as though the 22-year-old actress is single, bitter and trying to get someone's attention: Sure, Linds tweeted about Justin Timberlake supposedly cheating on Jessica Biel the other night, but we can only guess who "Sr" is in the last message. Samantha hasn't responded to one of Lindsay's tweets since June 12, and while we're sure they've been talking and texting, that's gotta sting! E! Online reports that the celesbians broke up on Monday night after a nasty argument, and get this - one of the biggest issues plaguing their relationship was Samantha's friendship with former Lohan gal pal Nicole Richie! A source tells E! that Nicole invited Samantha to a mutual friend's birthday party at Bar Marmont the other night, but with the stipulation that she not bring Linds. "Sam went to the party, and it really upset Lindsay." We understand that not everyone is a fan of Lindsay, but these two used to hang out all the time! Maybe mama Nicole doesn't want to be around Linds because she's such a party animal? Who knows, but the source added, "Nicole refuses even to be in the same room as Lindsay." Meow! Samantha had dinner with Nicole at Izakaya in Hollywood last night, and the source says the DJ broke it off with Linds shortly afterwards...and we're guessing that's when Lindsay started her pity party/tweet-a-thon. Other internet reports claim that it was Lindsay's hard partying and crazy behavior that lead to the most recent breakup. Apparently Sam tried to let Linds back into her life with the understanding that they would be just friends, but Lindsay simply couldn't handle that. So what do you think is the reason for this latest split? Nicole Richie? Cheating? Lindsay partying too hard? Or all of the above? And how long do you give it before the two get back together? You know they will!