Case of FIFO drastically lowering or increasing your capital gains tax?

Hi, I have a question regarding FIFO and how it can impact my capital gains taxes. I was looking through my capital gains statement (in my country, we declare in March) and it showed some losses being smaller than what they actually are, and some gains being much bigger than they actually are. A conversation with my broker told me that while my actual gains and losses may be what they are, the way that they are calculated for tax purposes, with the FIFO element getting into the mix, I could be subjected to higher or lower capital gains tax than what I had previously assumed based on my actual gains and losses. Is this correct? And if so, how do I avoid having to pay these taxes in the future? My original goal was to pay no taxes this year, which is why I took a loss last year. But given the way capital gains taxes are calculated, it showed that I had actually made money (when in fact I haven't) and now I have to pay taxes on top of the zero gains I made. Any insight into this will be greatly appreciated!