I need help with vocal tracks in Garageband

I am recording vocals for a song and I have one vocal part where my voice starts out strong, but then it weakens. I tried to just copy the good part of the track and just paste it and run it together to extend the "ahhh" i am having trouble with, but when i paste it, there is a tiny gap which causes it to clip. Is there a way to fix this?

You need to use a compressor to level out the dynamics of the audio.

you can eliminate the clipping by zooming right into the start and ends of the audio, and slicing it where it crosses zero, but that is a bodge job. learn how to use a compressor for the best quality.