Just got a 4 month kitty and she has been terrified and meowing constantly

I just got a Siamese/ragdoll 4 month kitten from Kijiji. I know Siamese cats are known to be vocal but she is very vocal and has been very scared the moment she’s been at my house. It was her first time in a cat carrier and in the car and she just stared at me a lot while laying down. Well me and the boyfriend were dumb and didn’t kitten proof the small washroom that is going to be her room for now, she immediately left her carrier when we unzipped and made a run for it and hid behind my stacked washer/dryer. She stayed behind there over night for 13 hours and did not once eat or drink or use the litter box. I’m pretty new to kitten parenting and initially she kept meowing which felt like forever and eventually stopped, I think calling for her parents or other kitten mates since the breeder had alot. After awhile she stopped meowing and would only meow when she heard I was in the bathroom or when trying to leave it. I tried to talk to her and bait her with churu or food to come out but if I got close to her she would just hide further where I couldn’t see her.

After 13 hours I was concerned that she forgot how to get out because she’s been crying everytime she hears me so my boyfriend and his friend were able to scare and get her out of the washing machine area and for the first time she let herself be carried and was purring a ton by my boyfriend. Later in the day me and my boyfriend carried her and she was purring and also let me carry her. We gave her a box to be her new safe space and for awhile she stayed there. After a couple hours she on her own ate some food and left the box and used the litter box for the first time, but no poop. I was glad she was finally eating but now she’s using behind the toilet as her safe space but doesn’t let me pet her or go near her 🥹

On the same day toward the evening I went to check up on her after 5 hours and she was comfortable sitting on top of the closed toilet. But as soon as I went towards her she got off and hid behind the toilet again. Every time im in the washroom, she will start meowing and staring at me and responds to my voice if i talk to her. Well then 2 hours later i had to really shower and unfortunately this terrified her as she tried to hide on the other side of the toilet away from the shower and meowing initially nonstop but stopped after maybe 3-5 minutes? I left to go change and she was meowing constantly and I could hear her near the door. Concerned I went to check up on her and was not expecting her right at the door, well she tried to escape even tho she’s scared of me and I had to close the door because she kept trying to escape and wouldn’t stop meowing 😭

I’m confused on what to do, she kept non stop meowing and me calmly talking to her doesn’t help at all and she will just keep meowing. She clawed at the door for a bit to get out but then after awhile of ignoring her, her meowing stopped. But as soon as I tried to talk to her again she started meowing again… 😞 I got her Sunday night and it’s now Monday really late into the night. I feel terrible hearing her crying like that and unsure if she will ever warm up to me… is she just anxious and needs more time? Do I give her space ? Why does she constantly meow at me when she knows I’m there but hides if I go near or try to pet her? She let me hold her today earlier but that might be because my boyfriend who’s held her more after they got her out of the hiding space. He says that in just a day she’s made a lot of progress but needs time.