[Help with Pen Tool paths and filling]

Hi guys, I'm a hand lettering artist who has just started vectoring my work again. My trial of Designer has just finished and I'm looking to purchase the software...but only if I can work out this issue I'm having. I'm sure its me not knowing the software, some help would be much appreciated. 

I've created the path using the pen tool (picture attached) which does have some overlapping. When I go to fill the shape, the overlapping areas don't get filled... I could not for the life of me work out how to get the whole shape to fill. I just assumed it would see it as a path that overlaps but alas...I was wrong. Any ideas? I'd be worried if this isn't possible, I can't be the only hand letterer using the software who wants to use the pen tool like this!

Thanks

 

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