Disappointed by my mother for not helping me. AIBU?

[Samafe]

So, let's start with 3 notes:

• English is not my mother language, sorry for any typo :)
• My mother is high risk population for Covid but she is now double jabbed, and me and my husband as well. 2yo son is not.
• We live ca. 2 hours far away

Covid hit my mother very very hard from the psychological POW. My mother has some previous unresolved psyc. issues but always refused psychotherapy, and Covid was really bad for her mental health.
My mom is 62 y/o and recently retired. She is active, mobile and with a modern mentality (at least before covid)
I have a 2y/o son and currently pregnant with DD in my third trimester.
For a series of reasons, I needed help and support few times in the last months, and she used covid as the reason why she could not help me, always in a very vague way like "oh, I would love to help you, but you know, it's a difficult time with covid…."
I needed to spend few days in bed at the beginning of my pregnancy due to an injury, she did not even bother come visit once. "Covid makes things difficult".
I got very sick last week, and even after testing myself with PCR test 3 times, she claimed that maybe the test was not accurate and she preferred not to put herself at risk, even after I cried on the phone telling her I desperately needed help (and I am the type of person that always says "no no, I got it").
On the phone she said she was heartbroken because she could not help me, even if she wanted to do it so badly. (FYI, tomorrow she leaves for the seaside, which is 6 hours away from her).
This was the last drop...I feel selfish because I understand covid is a big deal for her, but I am honestly starting to feel disappointment and resentment toward her.
There are many ways to support a person, and if she would "balance out" the lack of in-person support with another type of support (e.g. sending me cards or organizing grocery delivers or whatever) I would maybe feel better, but the only thing I keep hearing is "If only I could help you I would do it". Last time she visited me was Aug2020. In the meantime I visited her a little bit less than once a month.

AIBU for feeling resentment? Should I try to understand more her side? Do you have any suggestion how to deal with this?

Thanks a lot!

To be honest OP, I think you underestimate how debilitating suffering with mental health issues can be.

You say that you're annoyed because she says she wants to help but then doesn't - that could well be true. I suffer with anxiety and have done for a long time, there's been loads of times that I've desperately wanted to do something/to help but my body physically goes in to shut down and the thought of actually then doing it has me feeling like I can't breathe with the fear. I would be in no fit stage at that point to help anyone, let alone with looking after children.

Cut your mum some slack, it sounds like she's really struggling with covid. Maybe try talking to her and making a bit more effort to try understand it from her point of view, until you've been through that anxiety there's no way you can fully understand it but you can try

It's your husband's job to look after you.
Not your mums