Obsessive Aggressive Play

2.5 weeks ago I rescued a beagle mix puppy. She is currently just shy of 12 weeks old. This adoption was supposed to help me get over the loss of my dog in April. What was supposed to be a joyous occasion has turned into me crying near daily. First it was the separation anxiety—nonstop screaming. I absolutely cannot crate her without me fearing for her life. I’m chained to my house. We’ve at least advanced to a pen with lesser crying. Now it’s turned into her aggressively roughhousing me—like she does her toys. There is no distracting her. He is fixated in biting me—hard. I fear this getting worse quickly. It’s gotten to the point where she’s in her pen when she is not sleeping. That is the only time I’m happy. The only time she is happy is when she is allowed free run of my house, which she can’t have because she also aggressively roughhouses my cat. I have a first session with a trainer this week, but I am starting to doubt this will ever work out. I have never in my life surrendered a dog. I am considering doing so with this one.