My lovely dog, murtle, has recently over the past year has become an absolute terror to walk. We got her from dogstrust in november 2 years ago. She was about 9 months old, she is a bitzer, from what we and others think, has rottweiler and terrier, maybe a bit of lab. She was so amazing with other dogs, and with our cat, also with little children when we first got her, and for the next 6 months ish. Since then, she has become increasingly aggressive towards other dogs while out walking, which has slowly built up to us rarely ever walking her becuase we cant control her. We used to be able to take her anywhere and be able to let her off the lead and she'd always come back to us, and would play very nicely with every dog we'd meet. Now as soon as another dog has entered her eye sight, she turns and just goes crazy, and we can't distract her. PLEASE HELP.

I think you need someone to observe this behaviour to get a proper judgement.
Ask around locally and get yourself a recommended behaviourist