If you were genuinely too sick to work, it could've been your first or hundredth shift, the same rules apply. If this lady's being rude over that then it's her problem, not your own. If this lady carries on being rude then tell their superior you've an issue - this isn't the playground, there is no 'grassing' - if they're being unprofessional, the people above them on the pecking order have a right to know. Hell, everyone does.