Emil -
Welcome to CEG!
Yes, you have a leak. Find it right away; get it fixed correctly. If you park on clean pavement - and then pump your brakes (hard!) several times, you should be able to see drops of fluid somewhere under the car. That will tell you where to concentrate your effort first.
If you must pump the brakes several times in order to stop, you probably shouldn't be driving the car at all.
Yes, a failing wheel bearing can affect the ABS sensors - but you have other problems first. Perhaps the fluid leak is triggering the ABS warning light.
Get the brake leak fixed first; worry about other things next.