@Alex95 As mentioned, you need to use logic code, flags and timers to regulate the sending of emails… or anything else that can potentially happen too much too fast.
There have been many topics about this already and there is sure to be some examples floating around you can search for. Here is a generic timed action example I put together that, with some study, you could work into a “send email only once every X amount of time as needed” process
Also, you need to understand how to avoid populating such code in your void loop() when running timing and communications sensitive applications like Blink and other IoT.