Why do I feel bad for speaking up for myself?

I usually have a passive form of communication to avoid conflict but it does nothing but make me feel miserable on the inside and allows people to use and disrespect me. So, lately I’ve been trying to speak up for myself by expressing my needs, and learning to say no so that I could build my confidence and self worth again. Well, a situation just happened. I moved in with my mom and step dad because I’m going through a divorce. I have a huge TV that I told my ex to hold onto because there’s no space for it here but he insisted on sending it anyways because he’s trying to get rid of me. So it’s here, and we decided to put my TV in the living room and put the living room TV in my room. I don’t know where the miscommunication was, but they put my TV in the living room ✅, and put the TV from their room into my room ❎, and put the original TV from the living room into their room ❎. The TV from their room is small and theirs nothing wrong with that, but that’s just not what we agreed to. I felt bamboozled. Usually I would let that slide but I spoke up. We switched the TVs to what we originally agreed to but now I feel bad. Maybe this wasn’t the right situation to speak up on? Maybe I’m thinking too much... idk. I felt like I should speak up because I’m fair and considerate to everyone around here and I feel like I deserve the same. I pay rent here even though my siblings older than me don’t.

Where am I going wrong here? I feel bad if I do. I feel bad if don’t. Advice?