Brothers Girlfriend. PLEASE READ AND COMMENT!!!

Okay lady’s so my brother has been dating this girl for 2.5 years and in the first year she called me fat and disgusting and was trying to get buddy buddy with my mom. I got over it and worked it out with her and we were good. UNTIL she told my brother that she is better than me and she doesn’t understand why my husband is with me because im not a good person and just don’t have a good personality. I mean I was upset about that obviously and confused as why she was comparing me to her but also got over that. My husband is in the army and we moved to Germany a few months ago and we had to leave my dog because of laws so my dog is with my dad where my brother lives. Thanks giving was a little bit ago and my family members all told me that they can’t stand her any more because they feel like she tries to control of everything and “ fill my shoes” and this year was her first thanksgiving with my family...she has also taken my dog and calls it her dog and calls her self my dogs mother...my little sister is only 13 and is very impressionable and my brothers girlfriend has swooped in and is doing every thing with her. They now go shopping, get coffee, ect. She also talks crap about me to my sister. My sister has recently stopped talking to me and won’t even respond to any of my texts. I feel like his girlfriend has driven my sister away from me. I am BEYOND mad about this whole situation and not sure what to even do. I also feel like I might be over reacting but I’m not sure? This is only a handful of the odd things she has done as the list is too long for a post...lady’s I’m trying really hard not to go crazy over all this...my husband and I are going back home in 18 days to see our family and I’m not sure what will happen if i see her which I’m sure I will. PLEASE give me advice!