style - Displaying arrows on pipes from upstream to downstream using QGIS?

I am trying to display arrows on pipes of a sewer network so their direction is from upstream to downstream edges of the pipes.

I have managed to display those arrows on a polyline layer (which is the pipes) from the properties menu, but their direction seems to always be from Northeast to Southwest, regardless of the upstream and downstream edges.

How do i connect the arrow direction to those edges?

For example in the picture, the pipe between Nodes D11122 and D115 should have the arrow directed the opposite way.

Each pipe has an upstream and a downstream edge. Each edge is connected with a node and their properties are shown in the attribute table.