How long has he been in the house? I wasn't sure from your post. Depending on how you introduced them will result in their relationship... most often its advisable to separate the new cat for a few days or so for the existing cat to get used to the smell and idea of another cat in the house. This helps with the first cat's resentment of the second, and helps them both accept each other a little more.

Some cats need a month, some many months. Some only a few days. My Pouncer is a terror when new cats are introduced He's hissy and growly for at least a month, and then a month or so AFTER a foster cat leaves. Whereas my Harry loves the fosters and is always the first to bond and play with the new cat. My point is that every cat reacts differently to the addition of a second cat.

Try to make sure you give Meka plenty of one on one time and let her know you still love her. Dish out treats, making sure she gets hers first. Play with them both with toys. Soon she'll start to see having a new playmate is actually a good thing.