EvelcyclopS - I don't usually comment on these but you're post sounded so familiar - good decision making mate.
I'm sure you won't look back. In fact, I'm willing to bet that in 10 years time - you'll be in a senior extremely well-paid position in your microbiology career with your own home (mortgage paid off), something that you'll almost certainly never achieve in aviation - and also hold a commercial pilot license. You will have gained your PPL + night + CPL over countless weekends of having fun at your local grass strip and then be instructing in your spare time.
I made that same decision as you back in 1999 and boy I'm so glad I did. The opportunities that I've had could never had been matched had I been financially shackled to an aviation career.
When I look at the people I know who hold commercial licenses - most of them have main careers in other industries.