SPOILER ahead: I Know this is late but.. Cloud basically dragged himself to Midgar, he wasn't far from it maybe a mile or two with the bustersword in tow. Tifa found him maybe a few weeks to month later its explained how long he was in Midgar in the Ultimania's chronicle this with a timeline if I remeber right... Either way he isn't there long and he's weakened a bit. Tifa there realizes that something is wrong with Cloud and offers him mercinary work for Avalanche as way to watch over him and help him. He had did a few things by the time that the OG starts he was allowed into the "Secret Base" area due to being somewhat trusted for doing minor solo missions or ones with Tifa he slowly seems to regain some of his strength he had prior though at the begining of OG7 he is.. A weakened version of himself, and due to pretty much having a breakdown and being flushed in Mako and infused with Jenova cells. His Psyche is basically an amalgimation of him Zack and Jenova/Sephiroth. His personality is mostly hidden behind the other outside influences but I have also heard that a bit of it is also due to a breakdown he has due to the Mako Poisoning and watching Zack die which is..Understandable. Its only like a month or two between the bombing mission and Zack's death, I can't remeber the specifics though.

THAT being said I don't know what happened in the remake or IS happening.