Lately Alexa has started to get very very aggressive over the strangest things. She's been resource guarding more than she usually does, she's snapped at almost every single person that's come near here, she's almost killed one of the cats (she would have if I hadn't intervened) and she's just plain not herself. She's never shown aggression like this before. The only times are when she's playing and someone she doesn't know tries to take her toy or gets a little too close. She's always had some problems with resource guarding that I haven't been able to fix so this is normal behaviour. She has anxiety problems so being uncomfortable around people she doesn't know is normal. But lately her acting out has been ridiculous. She's never been mean towards the cats, she loves them and she's never been mean towards me, my boyfriend or my parents. I know when a dog's mood all of a sudden changes like this it can be a health problem so I'm going to take her in to the vet next week. My mom and I think she's constipated, or some sort of bum problem. She's had problems with constipation before but I've always been able to solve it with little home remedies. She's been going to the bathroom regularly but she doesn't have her usual appetite and that worries me. I'm just worried that this isn't a health problem because I have no idea what to do if its all behavioural issues. To be safe we're keeping her separated from the cats just in case. I'm so upset. She's been doing so well lately and has been getting over her anxiety and now this happens. I don't even know if I'm really asking for help from you guys, lol. I guess I just need some insight. Has anyone ever had issues like this? Well I'm sure someone has. I know getting her checked out by the vet is step one. I hope its nothing serious and I hope that it can be easily fixed. I don't want my puppy miserable.