Yes it does get a bit protracted towards the end. I particularly enjoyed being taken to touching distance of the finish at about 11 miles! I did 1.27 that day. Be very surprised if i matched that right now.
Dependant on the session you did, it may adversely affect your performance. If you did a very gentle 5k much much slower than race pace then ok. If you went out and smashed it up then you will probably have residual fatigue in legs.