Working with part income support help please

[Itsjusme94]

Hi I'm new here and could really do with some advice

I currently work 10 hour so still receive some income support however I have just handed my notice in (1 month ) just because working evenings and childcare situation has now changed.
Can I call income support now?? and tell them I have quit and give them dates and stuff so I am not left with next to no money till it's sorted

Or do I have to wait till the end of my notice period when I am no longer working to inform them?
And how long will it take for my income support to increase again? Really worried that I will not be left with enough to support my son

Thank you