Audio recording problem !!

You are likely in Comping mode. If you are recording a different part altogether (like the first recorded part is rhythm and the second part is a lead) then create a new track. Take Lanes are meant for different takes of the same part so you can pick the best one. They are not intended for two parts at once on the same track.
 
If that is not what you are doing (maybe you want the first recorded part to be a back up/guide track to help you record the next take) you can switch to Sound On Sound record mode (right click the Record Button in the Transport Module and select Sound On Sound) and then in the same dialog (I think it is in that same screen but it is in the Preferences somewhere) make sure you do not have "Mute Previous Take" enabled. Now you will be able to hear the previous take(s) unless you mute them manually.
 
When a clip is gray it means it is Muted. You can unmute it by right clicking the clip and selecting "Mute/Unmute" or select the clip and press K. If you are in Comping mode all you have to do to unmute a clip is use the Smart Tool to click in the lower portion of the clip but this will mute the other previously audible take (this is part of the Comping mode features).
 
The reason you got a hole in the clip is likely because of the Comping mode feature where it splits takes up automatically where there is an overlap with other takes. So you probably had splits and then deleted that section. Hard to tell exactly though without seeing exactly what you did.
 
Cheers.