Dropped from 1450 to <1300 Help wanted

Hey guys, I've recently found myself in a downwards spiral in ranked. At around the 1450 level, I wasn't able to play my usual position at AP mid, but rather was forced to play something a little less significant in being AD bot. From then on, I've been doing pretty well in lane, usually getting a kill and averaging about 60-70cs@10 minutes. But no matter how well I end up doing, I feel like the other lanes that I play with end up feeding. Is there any way to make my presence as AD bot a little more...impactful? I feel like the game's already over before I even have my chance to shine.

But moving on, I have found myself losing and losing despite (usually) doing competently in most respects. I'm able to keep up with my 1600 friend with harass/farm as mid when we 1v1, but yet I find myself losing to "stupid things" at the lower ELO. Where I used to dominate games, I find myself stagnating more and more the lower I sink. Any sort of help/coaching would be greatly appreciated, thank you for your time.

For champions that I play for the various roles Vayne/Sivir -> AD Kayle/Shyvana -> Top Shyv -> Jungle Ahri/TF -> Mid Sona/Soraka/Janna -> Support

ign:Optimusprime78

Sorry about the formatting, I apparently fail at making a list ><.