What do i do when im going through a phase?

Im in silver 5 currently i started the season placed in silver 1 and got gold in preseason. Lately im just at a point where i get out mechaniced by everyone and out played which is out of the ordinary. I tried watching pros and high elo streams and doing what i see and learn but it doesnt seem to be working out for me and everything i do that i saw them do in those situations im getting matched by my opponent in the same way. I cant best anyone right now no matter how hard i try. Ive dropped several divisions and im on the verge of bronze and i havent been bronze since the beggining of season 3. Im a mid lane main. I particulary like assassins. Im litteraly on a 20 loss streak almost aside from 1 win which was just lucky because i didnt play like i deserved it. I tried taking a break and thinking things over and when i came back it was just as bad or worse than before. I dont understand how i was able to just lose all my skill or did everyone just get alot better than me really fast?