if you have a cat and are on tonight

I'm scared .... I have a feeling this stupid rabies vaccine did something nasty to my sweet little Furball. When I came home, she had pooped on the carpet, and urinated on the bathroom sink and on the linoleum kitchen floor. She was hesitant to go near any of those spots, so I figured "she messed, mad that I was late from choir tonight... I'll clean it up"... About 20 minutes later, I noticed Furball is horridly angry with her own reflection in the dishwasher... so I slowly moved away, and offered her some water as a "peace offering" .. she seemed to be glad to get that water dish (normally in the kitchen.....). I came to turn on the pc, then remembered that she usually likes company while she eats... so I went over near her food dish. She immediately! got cute.. purring, snugglign, all the normal Furball stuff. All at once, she snapped onto her back, hissing, all claws showing . Scared me half to death. So I sat still, didn't move. When I did move, she made a noise that sounded half like a growl, hafl like a small dog howling.

Folks... what's wrong here? ANy ideas at all? Is it a side effect from the rabies shot she had last Friday? RIght now, she's sitting ontop the computer desk, watching me, cleaning herself, and being as cute as can be. She attempted to climb up on my shoulders about 2 minutes ago, then decided against it. I'm afraid to motion to pet her, because obviously she's upset about something ...

HELP! I'm worried about her ...

-Jennifer and Furball