Maya does that too. She gives me the "no body loves me look" if Im giving attention to Daezie or Luna and walk away to hide far way from us.
Once you have more than one is hard to give attention to one but you find ways to make up for the time. LIke othes said here, seak out. I do that If i'm running an errand I'll take one, then the next time I'll take the other one and so on. or when is time to brush their teeth is time that I use to bond with them, also when is bed time I rub their tummy massage their body.
I think in my case getting Maya was the right choice. Daezie has a little sister that she loves and play with they way she wont play with me, the chase eachother, wrestle eachother, pull eachother tails and ears, bite eachother legs. I love seeing them have a good time.
I dont think you will feel bad if you bring her a brother or sister.