Q: revving?

Yesterday i went up a hill wasn't a crazy incline but was a continuous hill that cars nor ally have issues going up. Car started to slow down was in third gear doing now 50km reving at 5000rpms then began a rubber smell through the vents. Pulled over to check on engine with what i could see everything seemed fine. After having to pull over twice then conquring the hill came onto flat land and could teally smell that rubbery smell just sitting in a parking lot. Driving on a d Flat road it seemed car was fine again running good. Today went to head off to work to get into work have to go over a hill though different type of hill never had an issue going over this hill since having the car today my car couldn't make it over it that i had to turn around. I changed oil amd checked on spark plugs which are still clean and fine. Bought a air filter as to thought it may help but not to sure. What could be the problem? Fuel pump? Fuel filter? T.i.a
My car has a manual transmission.