I spent three years working in biomedical research labs during my first underrgraduate degree. I observed graduate students putting in 80 hours a week on their projects for months on end, and in some cases the results were not even publishable. I also saw them trying to eek out a living for five to seven years on the $18,000 a year stipend they received from the university. Having an outside job was nearly impossible because of the demands of their research programs. After graduation, they had to look forward to $30000 per year as a post-doc, and they still were going to have to fight it out for a faculty position, and for tenure if they were lucky enough to be hired at all. If the position was halfway across the country, then they had to be willing to pick up and move.
The grad students were shocked that I was going to come out of undergrad (clinical laboratory science) making almost $20 per hour- to them this was a lot of money.
For all of these demands and sacrifices, none of the graduate students voiced any regret about their decision to pursue a PhD. They genuinely loved their work, so I don't think that they minded coming into the lab at midnight to check on their experiments. For me it was a little too much job insecurity and too little financial security for me to stomach, so when the time came to go back to school I chose NP. In nursing, you are pretty much guaranteed that you will be able to find a decent-paying job in any area of the country. Plus, I think that I would really miss the patient contact if I went into lab research full-time.
Good luck with your decision- only you can figure out if the sacrifices are worth it in the end...