Yabadaba88

Hello everyone! So I had to jump start my car a couple times lately. I have a new battery I purchased 2 months ago. I have a alternator I just need to install it, but my car hasn't been turning on so I néeded to jump it a couple times. Now I noticed one of the cables on my battery is also loose and when I pushed it down some, cars electric started working again. And I could turn it on...but now when it's on it kinda shakes, and I smell sum burny after a while, check engine light keeps blinking too. Idk what to do at this point, I'm affraid to drive the car. Having someone come check it out Friday but would love some opinions here from you guys! Ty in advance!