I recommend IM Jeremy SIlman's 4th edition book, How To Reassess Your Chess. This is a classic and great for teaching middlegame ideas.
The only drawback is that the lowest rating puzzles in this book are 1400 if I recall (and the hardest over 2300 or something like that), so this book might be slightly above your level right now.
It is still a great book for middlegames though, so I say you have two main options:
1) Wait until you are higher rated (maybe 1400+ chess.com rating) before reading this book or
2) Read it anyway and understand that some of its teachings will require more effort for you to grasp or some of it might need to be revisited when you reach that rating anyway.
I had a similar experience when I first read My 60 Memorable Games by Bobby Fischer. I was 1600 chess.com level at the time, but probably would have been better if I was 1800+ to read that book. I knew the book was slightly above my level when I read it though. It didn't bother me; I just knew it would take me longer to read.
I struggled in my middlegame a lot. I don't have a clear 'plan' and I start to blunder and just lose. I want to get a middlegame chess book but I can't seem to choose which one. Any Suggestions?