All default output settings use no compression or only "lossless" (binary) compression, so inevitably they produce large files with heavy data rates. you need to use compressed files for smooth playback like H.264. Do a bit of reading up. This topic is covered widely here on this forum and the Internet in general.
well, the thing is, i didn't render it lossless, the file is only 830KB and it's 9 seconds long, first i did render it lossless and it was over a GB, so it seems to be something else
There's no way to tell what is going on without workflow and render details. It could be anything from a poorly chosen and setup format to comp frame size that is causing the problem. Generally you should be using the Adobe Media Encoder to render h.264 MP4 files using one of the standard presets. Any other options require a decent knowledge of compression and formats to reliably render files that can be played back without problems.