I don't remember how old your pup is, I'm assuming this is her first cycle, so you don't know what (if any) personality change she might have. It's possible that her heat cycle has something to do with her sudden personality change - and it's also possible that something happened (or maybe tiny things) that you many not even have noticed, but that was big to her, and/or things have been building up when she's been on walks, and now "she just can't take it any more" - or a combination or all the above. If your dad is going to walk her while you're away, I'd ask him to keep her walks short, keep her away from strangers, do NOT let anyone near her or let anyone pet her, cross the street or do whatever he has to do to "keep her safe from scary strangers". If she has started her heat cycle, you're going to want to keep her close to home anyway - you don't want any "unwanted male suitors" following her home
(and they will!!!). You may find that she goes back to her old self once she's finished with her heat cycle - or she may really need you to help her with some intensive, patient counter-conditioning and desensitization work.
As for your mom, I'd recommend that she not force a lot of interaction, but toss yummy treats here and there (maybe just kind of drop them as she walks by - drive-by's, if you will) - make good things come from
her and let your pup notice that, it could change her mind in short notice. Your mom shouldn't make a big fuss about trying to pet her, rub her, look at her, or make friends - just tossing a treat here and there and being non-threatening will do far more toward making friends and breaking down walls. Your pup will probably start wanting to make friends, afterall, your mom will be the one with the treats that rain from the sky!
If she's just about to start her cycle, you'll be back before she's finished, so you'll be able to see what happens. Tell your dad to make sure not to correct her or tell her NO! if she barks at anyone, just remove her from the situation, put her in another room (if it's at home, maybe if someone comes over, etc), or cross the street if they're out. You'll know when her cycle's finished if this change dimishes and she goes back to her old self, or if work is needed. Some dogs become very clingy, some very protective, etc - they're gearing up for parenthood
. I'd recommend you just kind of go with it, and endure for right now.