Stik
Firstly you have learned an important lesson, it doesn't take very long to get disoriented. It can happen to all of us.
Secondly, your attitude is exemplary, you will be a safe pilot.
Third, if you ever feel that you are unsure immediately call up 121.5 and ask for a training fix - within seconds they will tell you, without any fuss, a relative bearing to a town.
Fourth, if you are still unhappy, inform 121.5 that you are uncertain of your position and they will help you. Don't hesitate, D&D are there to help you and they will.
Finally, post PPL, it's worth spending more time with an instructor becoming comfortable with radio nav techniques (beacon tracking) and basic GPS use.
Then you will have two additional sources of nav info to fall back on.
And very finally, if you ever read the "skygods" on PPrune complaining about PPLs blocking their 121.5/guard channel, please ignore this, the UK authorities have provided the Training Fix and Practice Pan services to aid students like you on navexes, as an aid to flight safety.