Sandra Bullock says bad karma caused her to run into a wall at Disneyland.The 48-year-old actress exchanged playful barbs with 'The Heat' co-star Michael McDonald during a recent trip to the children's theme park in Anaheim, California, with pals including Melissa McCarthy, as well as her three-year-old son Louis and she thinks the wall incident was cosmic retribution.Â She explained: "We went to Disneyland - Melissa McCarthy and I - we took the kids, took a couple friends of ours from the film. Michael McDonald, who's in our film, he's very funny and he's just mean. He's mean - and it's towards me that he's mean, so I just decided I was going to be mean back. And so, he would do something and I would say something mean, but every time I did it something horrible would happen to me."I fell over the railing once. That was funny until I did it again. Then, after going on [ride] Space Mountain, all I remember is turning my head and there was a blinding light, a crack in my head, and allegedly my knees buckled. I ran into the wall. It was because I was being mean back and I guess he has a karma thing."Although she may have suffered a potential head injury, the 48-year-old beauty admits she was too embarrassed to seek medical attention because child-friendly Disneyland is known for, its tight safety measures.She quipped: "You don't own up to something like that. You don't say, 'I cracked my head at Disneyland.' I still have the lump. You play a nurse in films, you don't need a [hospital] - I can self diagnose."Sandra's run of bad luck doesn't end there, however.The actress reveals that there were many freak occurrences on the set of her new comedy - in which she plays a straight-laced FBI agent opposite Melissa's foul-mouthed police detective - including a scary shootout.Speaking on 'The Tonight Show with Jay Leno', she said: "The first week of shooting, a bus ran into our camera truck. Then, that same location, there was a stabbing. Where we were shooting, the police precinct was right there, so the stabbing happened right there and then the attempted murder was caught right there. It was an exciting couple of days."