I took my battery terminals off to clean them and when I was tightening the negative side post, I noticed as it was getting tight and i gave it one last turn and then it started feeling loose again. So I retightened it and left it when it felt snug. Im sure it wont hold up for long. Will I need to get a new battery sence i might of over tightened it and it may become lose..

Good chance you rotated the steel threaded insert inside the lead post. It may or may not hold. I would get a new battery just to be on the safe side.

If you stripped the inside thread there is a chance you can drill it out, re-tap it, and either install a helicoil or use an oversize bolt on the terminal. If you spun the battery lead post within the plastic housing you probably need a new battery. If this is an older battery (5 years +) I would just get a new one.

i've also been in this situation before, i got lucky and only killed the threads on the bolt, cost a whole $4 to replace both of them.

I will try buying the new bolts first and then go with a new battery if neeeded..