Oh really? No way!

Actually, there are multiple theoretical proto-modern languages, such as PIE (Proto-Indo-European, from which people believe all European languages and Sanskrit derive). However, there are also theories that waves of proto-humans left Africa at different times and then eventually converged and interbred; if they were different species, they may have had very limited communication abilities and would have likely relied a lot more on pheromones and gestures than we do now (probably to get across basic thoughts rather than to express complex ideas as we do) and probably constructed a very rough pidgin. Interestingly, it's thought that declension initially evolved because one group of proto-humans had jaws such that it was difficult for them to form words, so giving them endings to denote their place in the thought they were trying to convey seemed like a better idea than expressing every word individually. In any case, OP's therapist is a moron, and OP shouldn't let him or her take control of the sessions like that.

Oh, and John Dee isn't considered an authority on anything. I'm surprised they mentioned this as a real thing at your university. Incidentally, even though no single person arguably knows all the languages of mankind, there are computers that can compare stems and grammar and words to figure out whether languages are related or not. Similarly there is the whole field of philology, full of brilliant individuals who are dedicating themselves to deconstructing how languages are evolving and have evolved. You have a very limited grasp of the world around you if you think it would rely on a single person to know every single language perfectly in order to figure out how an older version of the same language would have looked or sounded.

I'm not at a university yet, I just heard a talk show about it and started looking it up and reading books on the theory of it, but thank you for educating me

Actuall, therapists or counsellers are rarely doctors. Many carry a graduate degree at least though and some squeak by with a bachellors.

It's incredibly difficult to find work in the psychology field without a doctorate. Very very few get jobs with just a bachelors.

Therapists usually have either a master's degree or a doctorate. However, in some countries, the U.S. for example, the title psychologist can only be given to those with psychology doctorates. The word therapist as a title is a lot less restricted than psychologist or psychiatrist in most places. Therapists can be from other majors than psychology like social work or counseling. Countries do have restrictions on the practicing of therapists like licensing and things like that, but as a title it is not as readily a sign of supposed knowledge level.