So, is something like shoveling sidewalks alright to do at this point in
pregnancy?

I think you've got to listen to your body, there isn't anything doomed
to harm you in shovelling snow, but then plenty of non pregnant people
will get a sore back after a hard session of work on something like
that. Your risk of that is going to be higher in your current state than
in was prepregnancy, but that could still be relatively low compared to
a lot of people, or not, which is why you have to listen to your body.

Cheers
Anne