career in communications with communication skills below par?

This is addressing the guidance counselor or mental health therapist or other type of direct-helping profession. You can do it, but you will have to get over, at least to a large degree, being shy. If you're afraid to speak, respond, confront, or discuss something with someone, your helpfulness is going to be very seriously limited. The point of working in that profession is to help someone, right? Start with helping yourself to get over the shyness and become confident in your interpersonal interactions. I think anyone can get over being shy if they're motivated enough. I would have considered myself shy several years ago, pretty fearful of talking to people, speaking in front of groups, etc. and I'm now regularly involved with teaching groups of people, and meeting new people for client intakes, working regularly with people, and I'm pretty confident about it. P.S. I once had a therapist who barely said three words during our sessions, so it's possible to be employed that way. Just as a note, this does not at all indicate that the therapist was necessarily shy. This could be a choice on the part of the therapist depending on her style of therapy. And if her choice not to be responsive to a client WERE actually based on being shy, she would be a terrible therapist.

You can learn interpersonal skills! I used to be painfully shy as a kid... I managed to function as an adult, but then I got training in negotiation and mediation and actually LEARNED how to interact with people. I always thought it was just something you have or you don't, but it's not! Join Toastmasters, read Getting to Yes, look for classes in improv comedy... all of these things will give you some tools for communicating better and being less reserved. Dale Carnegie is a good suggestion too.

FWIW, I once had a therapist who barely said three words during our sessions, so it's possible to be employed that way. (I didn't like her for it, but she must have been good enough for others to be in that fairly large practice.)

So long as you want to be around people, I don't think it's a problem that you don't speak out much. It sounds like what you want to do is listen, and introverts are perfect for that. So teaching might be a bit of a reach. But therapist, guidance counselor, social worker, HR, tutor are all decent fits precisely because you're an introvert. The hard part is networking. The more that your client base is floating around, the harder it will be for an introvert. So an institutional gig might be a better fit in whatever niche you find yourself. No matter what, networking is a must these days. Even an institutional gig will have turnover. So don't think you can play the introvert card forever. Play to your strengths, but shore up your weaknesses.

I don't think you can get away with being shy forever. It's going to hurt you professionally. However, consider the possibility that your warm-and-fuzzy nature is being taken advantage of by extrovert propaganda that tells you that the only worthwhile way to "help people" is by being a guidance counselor or some other person-to-person nurturing profession, and if you don't do something like that, you're not really "helping" people.

No matter what field you select, you're going to want to bump up your computer skills. You don't have to be a programmer to learn to make and use spreadsheets, some basic HTML, and that sort of stuff. Practice in your spare time, fiddle around with various programs, and think about taking a basic class, maybe at your local library. I can't do arithmetic in my head, but I can certainly use a calculator to figure out interest rates, etc..--it never hurts to get comfortable with life skills for living in the real world.

People with high levels of introversion tend to do better one-on-one - so, in my experience, teaching was a complete nightmare because of the number of children and the need to constantly be interacting - that was just overwhelming. Private tuition would work better instead. Therapists on the other hand often deal with one or two clients at a time and the job doesn't require you to speak a lot, it just requires you to facilitate your client's speaking. With that much Feeling, you'll be easily overwhelmed by too much stimulus and not able to give enough of the Feeling to others, which will be the thing that will drain and disappoint you. So maybe focus more on the one-on-one professions.

What skills do you currently have? That might help determine if there is a shift that could be made that uses your existing skills and gets you starting to use the skills you want to develop and use. Are you starting your work life or is this a midcareer transition?

My point of view is that in the world of work, degrees, and sometimes even skills unfortunately, count less than people skills, communication skills, and who you know, and therefore I would say to you that you should try to improve your inter-personal skills to the maximum extent possible but still within the natural parameters of your personality and comfort level. You could try something like Dale Carnegie. Push yourself out of your comfort zone to see how far you can go.