Lost flight path on the map, then ship fell out of orbit

[EngineerinSquid]

I had a vehicle making its way into orbit, had a flight path on the map until i decoupled my boosters and didnt look back at the map until my PE under the nav ball had me in orbit. When i looked back at the map that ship no longer had a flight path. manually worked my way into a stable orbit based on the info below the nav ball and left the ship to go back into the VAB. after tooling around in the VAB for a while checked the tracking station and the ship still did not have a flight path, so i took control again of the craft. when i loaded into the ship it now had a PE of -500,000 and was falling