So I went to the doctors today. He took my blood pressure sitting down, then standing up, and told me that I had lower blood pressure when standing, which isn't good (blood's not resisting gravity).
Now apparently this is due to the Keppra I'm now on (2x1500mg per day), namely the high dose. This would be a problem usually because it means if I go down on meds, I'd have more seizures, but as I had my UTI which lowered my seizure threshold when I had the last fit, I can go down on the meds safely now that it is gone.
So hopefully, I'll feel alright soon.