Everyone is crying while I’m just confused can someone explain everything that happened ...

I think it's better to be stupid enough to not understand what's going on than when u know what is happening but can't change anything. It Hurts so much(╯°Д °)╯╧╧

a bunch of people are dead or there is no way for them to be human now a lot of the theories are sudenly making more sense uh being in so much pain it doesn't even feel like pain anymore umm just dying people.

!Spoilers for chapter 138!
its canon now that the world of aot is in a time loop and what mikasa saw was the previous timeline where eren decided to not activate the rumbling and not sacrifice historia. Instead he ran away with mikasa and in his last moments mikasa realised they were in a timeloop and told him she was gonna 'see him later', meaning the time loop was gonna reset and the world would restart.
This means that eren literally had no choice but to activate the rumbling since he has tried the other choices in other timelines and none of them worked, because the time loop still exists.
Also Jean and connie became pure titans because the worm emitted some kind of gas that turned eldians into pure titans. Armin decided to kill eren with the help of the Ackermans and other titan shifters that cant turn into pure titans. After mikasa realised that eren had no choice but to commit genocide and that eren actually loved her and would run away with her in the previous timeline mikasa finally stopped depending on eren and in my opinion helped ease eren's pain by killing him

so does this mean the timeloop is endless/untouchable or could this timeline where mikasa kills eren, be the last and they can finally have peace?

I think that the timeloop ends because ymir met with eren. Maybe ymir was the one who triggered the timeloop and now having accomplished her goal the timeloop is no longer needed.

actually im pretty sure what mikasa saw was like a made up memory cause brainwashing doesn't work on ackermans meaning that she would have remembered every last repeating time also the rumbling was like done to start a new era where titans didn't exist cause after the rumbling in season 2 ending song they show people coming out of the spots where all the colossal titans stepped so like its a new era.

I dont think its a made up memory because it looks like something she remembered and its completely normal she didn't remember every timeline she was in. She probably remembered the last timeline only and that see you later kiss is the same line that eren heard when he first woke up from his nap in the first episode so they have to be connected somehow. Also, yeah the titans will most likely stop existing.

I am pretty sure that the titan thing it's like a revolution thing where no more titans exist also i read something and it said that eren became the bad guy so that the eldians are seen as the saviors because in the s4 op the lyrics say the angel wearing the devil's disguise. So like there is so much to the plot it is so confusing I guess we will probably finally understand in the last chapter.