You can stand up for yourself while still being nice. You can set up boundaries while still not closing yourself off.

I used to be as you are now. I doubt what helped me will help you but I will tell you in case it does. My biggest problem was I used to think I liked everyone. I tried hard to see things from the perspective of not just myself, but others also. This made me understand them a bit and ultimately like them. One day I woke up and realized I really DON'T like everyone and some traits people have are unacceptable to me. I began thinking about which traits I find unacceptable and recognizing when someone had them. I gave myself permission and acceptance when I didn't like someone. By allowing myself not to like others, I allowed them not to like me. I'm sure I have traits which others find unacceptable. Not all people dislike me but some obviously do and will and that's okay. Oftentimes the feeling is mutual.

I haven't let this change how to treat people however. The traits people have which I don't like are usually something caused by their upbringing so not entirely their fault. I only get strict with someone and behave less understanding if a person is intentionally being cruel to me or others. That I will not tollerate.

I hope you find what helps you. It gets messy always being a doormat. I hope you can dust yourself off and be more comfortable. Once you are more comfortable with yourself, others will be more comfortable with you. (((Hugs)))