Ahaha, that things happens, but remember, keep saving the maps you do everytime. Like if you do something that is harder or that you don't like much, save after that, or after you doing much things... I also lost man parts of maps, but not a whole one because I keep saving the maps. Learn by your mistakes and get better.
Good morning. But you want the solution in MTA or in the other map editor? You just need to change the rotation X or Y coordinates, from 0 to 90. Just press in "Movement" and than you'll see the coordinates each in 1 box (so you'll see 6 boxes), the last 3 are from rotation. It also works if you press CRTL+MMB (or RMB I don't remember now) but it will be muuuuch harder. Good Luck.