The way I get paid is about to drastically change. Can I stop it?

I'm an RN, in the ICU. The way we get paid is a tricky thing, and can vary a lot from one hospital to another.

I have a base pay, that is negotiated when I start. And is subject to raises, granted we hardly get them. About every 5 years hospitals do a "cost of living raise" and they also get apples to apples comparisons to surrounding hospitals and try to match up the pay, so a "5-10 year experienced ICU nurse" at one hospital makes about the same at another.

One only worked here 3 months, and they're doing what is effectively a cost of living raise.

As of now, I get a base rate of $25.30 (very low in this area, but that's a long story)

15% extra for being night shift.

$120 stipend every other week.

$3/hr critical care differential.

Supposedly, on the next pay period, my base pay will go up, but I have no idea how much, it may be 25 cents, it may be $5. However, I will be losing the stipend, and rumor has it I will also lose the $3 differential.

The only plus side, is that if my base goes up, then its compounded by the 15% night differential, and my overtime rate, which all nurses make a ton of.

Is there any way I can fight this or negotiate with it?

Some basic math says any raise less than about $3.50 will actually hurt me in the end, once you cut out the stipend and the critical care, $1.50 if you only remove the stipend.