Are you rolling the tops of your extensions after applying them? This could be breaking up the bond in that area and allowing it to wear away while washing, conditioning and rinsing the extensions in the shower.
Is your water pressure too hard? This could be wearing away the tip-top of the extension attachment.
This can be better avoided when applying correctly by as little touching of the wet bond until it cures (24-48 hours).
The tops will be the first area of the attachment to wear away but as long as the main girth of the attachment is intact, you shouldn't worry about losing an extension.
Those exposed hairs, along with collecting shed hairs, can be bothersome when the extension is growing out around 7-10 days but, usually, washing will turn those shed hairs down and allowing another week to pass will allow the extension to grow out a bit, and the culmination of these 2 tend to eliminate that feeling so that the extensions become quite unnoticeable in your head.