High pitch whine and shaking

So whenever I start my car, it feels like the front of it is shaking, also has a kind of high pitched whine, coming from the front of the car. Sometimes the whine gets very loud and I thought maybe I had a pulley seized up but it suddenly stopped making the sound and now it does it at random. Does anyone know what could be causing the shaking when I start it? Maybe a motor mount or something? Any ideas about the whine/squeal it's making at random? It literally feels like it's shaking itself alive when I start it up, it's very noticeable as well. Also, this morning I noticed that when I'm sitting in park, the back end now has this weird bumping sound, sorry, that's the only way I can describe it feeling. It's not like a shake, but almost bumpy and loud. I climbed underneath back by my muffler, and noticed the bar that's usually welded to the muffler and bottom of the car is broken somehow, could that be causing those sounds coming from the back? One last thing, when I go from reverse to drive, it feels as if my car wants to shut off and I have to quickly press on the gas to give her a little go and then she's fine, only once have I went from reverse to drive and it somehow shut off, I put it in park, started it and she started fine so I don't know. I also need new wheel bearings and maybe a rotor but I'm trying to find someone to help me put them on, but these issues are starting after already knowing I needed the wheel bearings and stuff. Please help if you can. Thanks.