If you think a marketing 9-5 is soul sucking. How do you feel about drafting bathroom stalls 9-9? But wait ! that’s not all! with a salary significantly lower than your marketing starting salaries. 

What is it about architecture that you've "started to discover"?

This is not a profession for week-end warrior romantics.  It still takes a long time to (ie. decades) to get to the point were you may be able to make significant moves.

I don't see why your background would hold you back.  You'd be looking at a 3 year Masters of Architecture program.  A ton (most?) of the schools now that have a traditional 2 year program now also have a 3 year program for those coming from non-architecture backgrounds.

In the meantime, I'd suggest using your communications degree and try to find a marketing job in an architecture firm.  This will at least put you in a position to be able to work around architects, learn some of the lingo, and see what the day-to-day is like.  You may find that this fulfills what you are looking for without having to go back and spend a ton of money on more education.  If you can afford to supplement this experience (with time and money) by taking some community college courses in softwares like AutoCAD, Revit, Photoshop, etc., that would help move you along and you could potentially begin to build a portfolio for applications.

The thing to know, in my opinion, is that there is a huge gap between what you do in school and what happens in an office day-to-day.

You mention drawing and design being a small portion of the work. That's not true. You draw all day unless you have someone else drawing for you. That is the medium of the work. I draw 10 hours straight at times. Throw out my back about twice a year just from drawing!

Read "Architect" by Roger Lewis.  Good overall view of the profession.  You need to decide whether the profession is going to give you what you are looking for before you start shopping for schools.

Your biology background might come in handy if you choose to (within an M.Arch or with a post-professional program) go the computational design / design programming route!

Programs like ICD/ITKE's ITECH, the AA's EmTech/DRL, ETH Zurich's MAS DFAB, etc. consider biomimetics (or biomimicry, might wanna read about this) as a paradigm and consideration in building technology, and best aided or designed with today's computational design tools (grasshopper, dynamo, etc). https://www.autodesk.com/redsh...

I’d recommend attending summer programs like GSD’s Design Discovery if you’re interested in exploring the field/don’t have much experience with architecture as of now. Other schools have similar programs (I know GSAPP has Intro to Architecture) but I attended the one at the GSD and loved it. If anything, it could provide you with 2-3 projects you can include in your portfolio should you decide to apply for an M Arch. Like thatsthat mentioned, many schools cater to the fact that not everyone applying has an architecture background - I’m sure you’d be able to include your communications work in your application portfolio as well!

run like hell. this profession pays shit. I’ve been interviewing like crazy and no one wants to pay worth a damn. After 10 years I’m burnt out and mentally and physically exhausted of the bullshit. 

Use your network and see if you have a friend of a friend who is in the design and construction industry, talk to them. Maybe you can get a tour of an office or of a project/ site. Also someone mentioned getting a job in the marketing group of an arch office, that's a great idea. Good luck!