I was taking some photos (I had got around taking 4 exposures) and all of a sudden (and this is the first time its ever happened) I was not able to take anymore pictures. It sounds like the Shutter Release button was on some sort of lock because each time I press the button it makes a noise and the film cartridge symbol and the line next to it blinks. I had the camera on Manual mode, by the way. I'm a noob with SLR cameras, so do you think I could've made a silly mistake and somehow flipped some kinda shutter release lock? Thanks!