What do you do to try to stop it?

Another approach would be to not try to stop it, but rather to acknowledge and accept that these thoughts are still part of you. You could acknowledge them in a sort of friendly way by saying to yourself "Oh, there are those thoughts again!" without judging yourself. These thoughts are just there for now, but you can go ahead with your day regardless. You could acknowledge nonjudgmentally the presence of these thoughts, but continue to maintain and follow through on your plans and commitments.