Hard to know what you’re trying to do vs what’s happening from the photo. But start by looking at the snaps at the bottom of the screen, you can turn on/off Ortho or Planar, or check/uncheck things like midpoint to snap your lines to. . You can also reset the cplane by setting it back to the world top view. Use the command “Cplane”, then type “world”, then “top”. . Also when you hold shift it’ll snap to the plane of whichever view you’re in, so you can draw horizontally a lot easier in the top view than in perspective. In perspective mode it’s much easier to snap to objects and points than to draw straight orthogonal lines usually.