Oo normal yan, mama! At 8 months most of us are so tired kasi ang berat ng belly at the hormones are all over the place, a few of us in our mom group actually complained ng same thing, parang our bodies just want to shut down na. The double vision when you're super sleepy is a bit concerning though, so I'd really suggest checking with your OB just to make sure everything's okay, especially since you want to rule out anything else. Get that rest when you can, alam mo na yan na lang ang kaya natin ngayon! Congratulations on December baby!