Dogs behavior switching

Hello there!
I'm new here and looked over the rules so hopefully there is nothing wrong with me starting this thread.
I am seeking advice so please, if you think you can help, read on and comment below.

I have two rescue dogs, a sheltie/corgi mix who was very abused at his previous "Home". When I got him, he had scars on his head from abuse and whenever someone came by, he would roll over to submit and often urinate on himself and others. He is still very submissive but has become much better and now enjoys meeting new people and other pets.

2 Months after copper, I received another rescue, a lab puppy who I named Lilly. With a bit of abuse history, but more neglect than anything. I got her at maybe 2-3 months old. She was not fond of women and while tolerating me, ADORED my fiancee who was living with me. About 2 months after we got her, I found out that he had an alcohol problem and had started getting into very serious drugs. He had not only spent all his money on them, but also stolen money from me and my family members. I asked him to get help for an entire month and well...things escalated one night to the point where I didnt feel safe. I told him he had to leave until he got therapy. While that itself is a long story that I dont want to go in thorough detail about unless needed, I state it because he was Lillys favorite and she was heartbroken when he left. Then got angry and began destroying any clothing he had left behind and for a while, had a problem with any guy who looked similar to him. However, after a month, she got over that issue and started liking all men and women who came into the house.

She has always been well socialized, never shown any problem with other people or dogs...until one month ago.

A little over a month ago, her personality seemed to switched completely. She went from being semi-independent, to now being constantly glued to my side and often always trying to crawl into my lap. Shes also started to display jealousy for even inanimate objects. I work from home and most of my work is done on the computer. She has started getting up and trying to knock my computer down, kicking it, and the same with cellphones. She has started to wait by the window just to aggressively bark at anything that comes by (Car, person, or dog). Shes been jumping at every sound to try and go attack it. Shes also been freaking out horribly at storms recently, getting so scared shes started shaking. (When I consulted some of my friends with dogs about her sudden fear of storms and why it bothered her now and none in the past, a few suggested maybe it was air pressure change since we are in tornado alley and the storms recently have all had tornado activity)

Shes really only been at my house or at my parents house for the first week or two of this behavior change. But when I started trying to take her on walks or running with me again like I used to, shes started trying to pick fights with other dogs. It switched all of a sudden and surprised me that without even small signs, she just started to freak out. I had to grab her around the chest to stop her from charging at a dog on the other side of the block. She then took this aggression and pointed it towards copper making him submit to her. I started taking her home from the walk when she then started displaying this behavior towards any person she could find. Maybe I shouldnt have taken her out, but she has always loved going around the neighborhood! It was a nice day and I thought she and copper would enjoy it.

I have her signed up for private lessons both for listening and with a coach who specializes in aggression. Since this behavior switch is so new and sudden, and now that I know aggression is involved, I want to seek help immediately. Thats also why Im on here. There have been no environmental changes. But I want to see if anyone can give me advice for things I can do to calm her down. Im of course not a professional, but Im just guessing this behavior comes from nerves. I'm hoping to hear ANYTHING I can do to help her before the training session and so Im hoping some of you may have experienced this before or know of some things I can do so Im not wasting any time and allowing this behavior to grow until her coaching session.