Weird glitch

Hi everyone! Today i was experiencing this bug that keeps happening. its a glitch whenever i delete a large object with alot of parts stuff happenes. I cannot make my camera go closer to the craft, and it flings me or my camera goes away from the craft, the GUI stops working, meaning when i press any button it just makes the pressing sound and does nothing. Please fix this bug and it has been annoying me. Thanks! P.S this happens in designer mode.