need help - audio and preview issues??

so whenever i use an audio, it doesnt sound like the original i put in and sounds rlly weird. but when i export it the audio is fine, but its very hard to edit with the audio sounding so weird. and for some reason the preview is realllly slow (maybe thats why the audio sounds off) and i cant watch whatever ive edited in one go, it only shows a few seconds of the edit and then returns to the beginning

for the audio issue ive tried stuff like changing the file type 

and for the preview issue i tried changing the settings related to the frame rate but everything ive tried on the net, nothing seems to work.

im not good with technical stuff im just a teenager who wants to edit, i tried to describe the issue to the best of my ability