Where is the main-quest gone in RDR UN?

I have been playing RDR UN for a small amount of time now, and I was enjoying it. But I understood that there were cheats available for the game, and I decided to check them out. So, When I came back to normal game-play, the letter "L" had disappeared on my map ( it was the only letter left seeing that I had completed all of the other letters before and this particular "L" was the first in that sequence.)! What in heavens name could have happened?

thank you for your very supportive answer, I'll take it into consideration.

bump

Press start and look in your journal for your quests, I thought I ran out of quests too cos there was no letter appearing on the map, so I checked that Journal and found out I had to collect some flowers for that mentalist salesman. P.S. another annoyign problem I had was when I was trying to travel to a destination I was getting annoyed because I didnt know the name of the towns/settlements, so press RT to zoom in and see the names.

yes, that may be the solution, if I recall correctly I have that quest still open. thank you for your comment! (Y)