Yes kids (especially around that age) will show jealousy when they get a new sibling. From their point of view they go from 100% attention from both mom and dad to half that. So of course they have reasons to be jealous.
What is important are two things:
a) Make them the older brother/sister. If you tell them "oh i'm so proud you can put on your clothes yourself. Maybe you can teach little jimbo later how to do that" you take away the competition and make them part of that new, exciting (and sometimes annoying) life that joined the family.
b) Make sure you keep having dedicated time for each sibling. It might feed like everything revolved around the new baby. So make sure to pay extra attention to the things revolving around them too. Especially as a dad you could even "send away" mommy and the baby in her belly and play a game with your kid. If you make this obvious that every week you play a game with her and no other people can interfere with that it helps her feel safe. Make sure once the baby is born you keep this time and 1 parent does something with the baby and the other does something with the other with your daughter to make her feel special.
As far as aggression it might it might be just the 2 year old having a fit of frustration when she was tired. 2 is the age that tantrums also appear. Generally speaking make sure she doesn't get anything from a tantrum and make sure she gets enough fun as mentioned in the 2 points above. Be careful though not to give special attention as a result of her being angry, because then being angry becomes an effective way to get your attention.