Difficult to say from these photos, but this looks more like a missing sector orb weaver to me (Zygiella x-notata). Very common around & sometimes in our homes, harmless.
The larger image seems to show a brown head, with a darker central stripe, wider at the front - false widows generally don't have this kind of marking. The marking on the abdomen looks more like a "flare/feather", in a young Steatoda nobilis this would be more like a shield/pentangle (a mature Steatoda nobilis, which might have faded markings, wouldn't have stripey legs). Have a look at the web too, is it a classic orb web? Steatoda nobilis make messy, shelf-like webs.
You may well see an egg-sac, but they also make little sacs that they hide out in during the day.