Is it okay to only eat 2-3 slices for breakfast?

Generally speaking 2 or 3 slices of bacon won’t do you any harm whatsoever. In fact it may not be enough as some of the others have pointed out.
As for the flax seed well that does rather depend on what you’re having it for. If you’re having it because you think it’s a good idea then perhaps you could swap that out for something that gives more satiety through having a higher fat content such as cheese or that sort of thing. If it is because you think you need the fiber well that’s a personal decision. Only you can judge that particular need.
The truth of is it though the more you get in to the low carb way of eating the less you’ll find that you need to eat each day as the generally high quality food that we low carbers tend to eat means that we just need to eat less to be just as satisfied as we were on a non low carb diet.
Hope that helps,
Mark
This is a copy of the comment I made on a forum post about bacon