I was listening to a speaker tape, and the guy was saying about a sitcom he watched where this overbearing mother visits her adult kids and is really critical. The son takes it all completely to heart; twists himself in emotional knots; and when she leaves, ends up in a state for weeks. The daugher, when she is visited and received the same nagging and criticism, just laughs and says "oh Mom!" and then forgets it. The speaker was pointing out that there will always be 'stuff' going on, we just need to learn how to deal with it so we don't keep giving ourselves a nervous breakdown when we could just "Oh mom" it.
You don't have 2 choices about this. You have 4.
1) Decide not to take sponsors advice; and thank her for her advice and concern, and assure her that you'll consider trying it her way if the exercise stops giving you some kind of relief,
2) Decide not to take sponsors advice and still twist yourself into knots about it, and spend hours projecting about what might happen tomorrow / next week / when you next speak to your sponsor and feed that resentment.
3) Take sponsors advice. Accept that you are choosing to take her advice because she might know something you don't (or even be suggesting it on something you're forgotten) and go to the meeting with a willing heart in the frame of mind where you can listen and learn from it.
4) Take sponsors advice but be resentful about it, and sit at the meeting in such a state that she and everyone else thinks maybe you need even MORE meetings.
Only you know how each of those options is likely to make you feel. This is your first post (that I could see) on SR so we don't know the background to this (i.e. if any of the premonitions of doom delivered to you from your sponsor have any likelihood of happening).
You say that she is making you scared. If her suggestions of what could happen are completely out of the blue; your program has been working well for you of late; and you have not spoken to her about possibility of relapsing, then assure her of those things and choose (1) not to be scared and (2) not to take her advice. Kind of "Oh Mom!" it.
If you think that you may be less stable than has been suggested here, and she could be right, and she's supported you well so far, and the trust you put in her throughout working your steps has proved well placed, then perhaps try to get to another meeting. Does it have to be the Monday night one? Are there any lunch time ones that your employer would be willing to look on as like being a doctors or counsellors appointment and let you have slightly extended lunch hour for? Could someone watch the kids for you on another evening so you could go to a different one?
Def worth using the resentment prayer though. We're talking about the choice between a spin class or a meeting. I know you've also mentioned the scary way she spoke to you, but I get the impression that you were already bristling about having to miss your class before that happened. (Apologies if I'm wrong about that). I think this is more about a battle against your self-will or similar than a spin class, which is why I suggested working through that resentment (step 4 style.) If nothing else it should take the power out of it and you can regain some perspective and calm.
Hope you feel better soon. x