Lohan's getting crazy -- and I don't mean in a good way. We watched the girl party from late last night until 5 am when she arrived at Paris' house (hiding under a blanket -- see video), to around 6:30 this morning when she finally left Paris' house. Girlfriend was so messed up she trapped herself in between Paris' gates and then hid behind the plants until someone could come let her in. Then she hid behind a pizza box on her way to her car, throwing it in the middle of the street before she got it. She then thew something else from her car at one of our photogs.

So maybe she just doesn't like photogs, you say. This is possible, but it's not cool to call the cops and claim they're carrying a gun (like she did a month ago) or to drive around with her hazard lights on, endangering herself and others on the road.

X17 caught Lindsay staying up all night twice this week and our eyewitness photogs have said both times, that she appeared to be seriously messed up.

Watch and speculate ...