2006 Ford F-150

I was driving on the highway and I had a little over a quarter tank when all of a sudden my low fuel alarm went off. On my display I had it set to show how many km's left till empty and it said about 60km which was weird. Then I noticed it was going down rapidly but my fuel gauge was still at a quarter tank. It went from 60km to about 40km in a very fast manner and I panicked and was about to exit the highway then it reset and went back to 141km's to empty. What happened? Is it something I should be concerned about? It happened twice on the same day. Please help, Thanks