Welcome to the Magix Sound Forge users community @GENOVEVO-IZAGUIRRE.

Are you using the 'Stop' button in the Sound Forge Transport or the keyboard 'Space' key? If the options settings are set so, using the space key will rewind and overwrite what was previously recorded when the space key is pressed again. The transport 'Stop' exits the 'record ready' mode (aka, Arm). If your wish to 'Pause' and resume recording, press the 'Record' button (or the keyboard shortcut Ctrl+R). to toggle Record/Pause. The record 'Rewind' setting, is in the "Options> Preferences> General" menu. The recording UI and settings has been changed a few times. See this post regarding SF Pro 15.

btw, please include what version of Sound Forge you have... Read the 'Sticky' at the head for the main Sound Forge forum page.