Does joining Power Bloc means that you automatically loose your market?

I’m playing Sweden and recently got invitation from Prussia to join Zollverein. However what I noticed is that I lost my own market and I don’t have influence on taxes anymore. Question: is that standard when you join, is that more beneficial for me or contrary (1855 year) and is there any way to reclaim my own market or just leaving power bloc? I’m playing with all DLCs