We rent a cottage that has a septic tank. The tank has to be drained quite often as rain water and garden hose water leaks into it and fills it up. So it has recently been emptied. However, for the past 10 days or so, there has been a TERRIBLE smell coming from a drain about 2 meters away from the septic tank area. I am not sure if there is leakage or.. We have been experiencing a bit of a heat wave lately and it could just be over heated poop or something, but we can't have our windows open due to the stench! Is this dangerous to be breathing in?

Yes, septic tank gasses can cause health issues and other dangers like methane gas explosion hazards and asphyxiation hazards. You should repair the leaky faucet and route gutter runoff and storm water away from the septic tank and leach lines, if present, to avoid this problem.