Do you keep the heating on overnight as well? Maybe a little heater on low overnight, if not the central heating. Night time is when they are awake and active. It is really cold at the moment as well. She may not survive going into hibernation again (if that's what is happening).
Also does she have a big enough house to build a nest in? Or a big enough nest. Our hammy builds a huge nest in winter and packs loads of substrate in all the gaps, to keep warm. He also has a good few inches of substrate beneath his house.
If her house is a bit small try making a shoe box house. Cut the bottom out of a shoe box and a hole in the front for an entrance door and use the lid as a lift off roof (so you can check inside without taking the house out so her nest doesn't fall apart).
Putting a bendy bridge over the door will also help keep it dark inside and keep draughts out. And put a huge pile of torn up strips of plain white toilet paper out in the cage somewhere so she can take some and make her nest bigger. (it's the safest nesting material and they like pouching it and weaving it into a nest).
Ten months isn't very old and I'm guessing this is her first winter with you. We have a little oil filled radiator we leave on low overnight in the room our hamster is in. You don't want anything that isn't safe left on (eg radiant rings) You can also get these
It's a microwave "hot water bottle" for pets. It's a hard thing in a fleece cover. I attach it to the side of our hammies cage at night with one of these! I hang it on the side of the cage instead of over a kitchen door, and the snugglesafe pad sits in the gap with the front bar holding it in place
so it sits on the side of the cage next to the house area. It isn't that warm by morning, but helps - although it's no substitute for keeping the room warm - I do both.
Demonstrated on photo below!