So you're going into your senior year?
Here is what I would do if I were you. I would not get a masters, yet.
I would study all summer and get a great DAT score. Then I would aim for as close to a 4.0 next year as I could. Meaning maybe a few A- but avoid any B's like the plague because you cannot afford them.
Ideally you could take 3 sciences and 2 non-sciences as a schedule per semester for fall and spring. Be strategic about this so you don't take them from the hardest teachers or too many of the hardest classes.
If you can put off graduating for a year, by purposefully not fulfilling all your degree requirements next year, then repeat 3 sci + 2 non sci / semester @ 4.0 the next year too. Then apply with a solid DAT, an upward trend, and a BCP hopefully above 3.0.
If you're able to get the BCP above 3.0 prior to this and really do well on the DAT I can see applying after your 1st senior year.
If you did this successfully I think you could avoid a masters; but, it wont be easy to achieve and is no assurance of success.
***EDIT: also really focus on why you've been getting such low marks. You'll need to address that in order to move forward. Most likely it will mean a drastically different approach to how you study and how much time you spend studying.