[Q] Note wierd battery problem

My note is only 4-5 months old.
But what happened 3 days back was I only charged my phone to 50% in the evening and took It off, then I must have used it for 2-3 hours in night and then went to sleep.
Next morning it was 25%, I used it till 5 and then tried to charge but it won't recognize the charger.
And keep switching driving mode and s voice on and off.
Then when I restarted it, it shows 40% battery from 5% without me charging it at all.
From then on the charging problem was solved but
It goes 100-60 in 2 hrs (idle)
And rest 60% lasts a bit longer ?

Thanks for ur replies and interest.