Your mom needs to get a life.

You're trying hard not to be hurtful to your mom. In return, she's being intrusive to the max, which is a shame. Does this lady perhaps qualify for a psych diagnosis? I think you have to set limits and actually tell her that you are doing so. Maybe say, "Mom, you're getting obsessive, and this is not healthy for either of us." Start with limiting her to one call per day. Also, change the topic when she keeps digging into one thing. (I don't say that's easy to do.) Nobody enjoys being interrogated. Maybe say that, like: "Mom, we can have a conversation, but I'm not going to be given the third degree.)

I think she's counting on you not wanting to be hurtful or sound insolent. But she's taking advantage of that. Sometimes you have to put up a barrier, even against someone you live. You would think 100 miles would be enough, but apparently it's not.

I hope things improve. This is too much day in and day out.

And don't let her guilt you.