It is hard to know what is going on without looking at your query but there are a few things you can check.
Generally when I am pulling data into power BI I will set up the query and edit it in the advanced editor (right click the query in the left column list of the transform data view). I would look at a the date range here to make sure it is as expected. Also make sure you are looking at the correct report suite. and have the correct attributes pulled. If you are pulling back aggregate data you wont hit the row limit but if you are trying to pull hit level data it is easy to max out.
Also be aware that Adobe showcased a new database connection for CJA that will remove the row limitation. This should be available in late may and is only for CJA.