Drooling and not eating.

My female cat, Patches, has been with me since I was young. She has never been to a vet and only went outside before I got her. She is about nine or ten years old(I'm not sure since we never really celebrated her birthday) and not once has she had a health problem. Well, that was until about four days ago when I found her lying outside my bedroom door, drooling. Patches is normally the kind of cat that doesn't like other people that much but will go to the ones closest to her to be pet and to meow at for seemingly no reason(Half the time with her, that reason is because she wants treats). When I saw her lying near my door, I walked close to her, expecting her to look up and meow loudly or run off. Instead, she just lied there, doing nothing. I got on my hands and knees to see her drooling. I reached out to pet her, earning a quiet meow and her running off under a table. I followed her and picked her up, something she normally hates, and just held her for about a minute, looking at the drool. It wasn't much drool, just enough to make a small buildup on her chin and drip down to the floor every now and then. I put her back down and she ran and hid under a bed in another room. I checked up on her about ever two hours, only to find her still drooling. The day after that, when I first checked on her, she wasn't drooling but she hadn't eaten or drank anything and she didn't use her litter box. I started to freak out a bit when I noticed that but left her alone, hoping she would leave the bed and act like she normally did. I continued checking on her about every two hours, with little happening to her. The second to last time I checked on her, I got some soft treats, combined them with water, and tried to feed them to her. She ate some so I did the same with her hard cat food, witch she didn't eat(I think the smell of it made her not want it). Day after that(Day three), I used some hard treats instead of the soft treats. She seemed to like that, but wouldn't eat it out of the bowl. Throughout the night, I would feed her the treat-water mix with a spoon to make sure she ate at least something. On the forth day, she left the bed. She had used her litter box and ate some of the treat mush on her own. I made her some more, adding a bit more water than before, and continued to feed her. At about four am, she left the bed again and sat on the couch for a bit before going back. Day five, today, she was out almost all day. She ate some more treat mush, used her litter box, and has been in a good mood, meowing at me and letting me pet her. I'm still worried about the amount she is eating and drinking though and what had caused the random decline of health. I don't have any plants in my house and I don't think anything in the house would get her sick like that. I have yet to check her mouth, just because I don't want to stress her out by trying to look. Do you have any ideas what could have caused it?

I got her some normal wet food today(Meow mix I think) and she loved it! She ate almost the whole thing, which I think is odd. She normally doesn't really like wet food but I guess after eating the mush she was eating before, the new food was an improvement. She has started using her litter box more and has been drinking her water again. I checked her mouth and didn't see anything so I think it might just have been nausea... I'm still going to be keeping an eye on her just to make sure. Could fear or a fall cause nausea? We've been having bad thunder storms recently and a few days before she started drooling she misjudged a jump from the back of my couch and fell a bit. She seemed fine at the time and just got up and walked it off like she does when she always falls. I'm going to get her a new carrying crate before I take her to the vet, which should be tomorrow. Thanks for your help!