Hi, I just got this plant about a week ago and transplanted it into a new pot two days ago. Before transplanting, the leaves were really healthy and new growth was occurring. After transplanting into a bigger pot, the leaves started to wilt overnight (I see it when I wake up in the morning) so I try to give it water and after an hour or so in the sunlight, the leaves perk up again. Also, the top leaves (newly growth one from the original container) are starting to turn brown (in the picture, you can see the very top leaves browning near the edges). I have been reading around the internet to make sure what type of symptoms it may be showing.

Overall, the only symptoms that my plant can relate that I could find is either transplant shock or over watering. If you guys have any advice it would be appreciated.
Thanks.

Other information:
Temperature of room: 70-80 degrees
Sunlight: 4-6 hours of direct, 2-4 hours after of indirect
Water: Once every two days
Soil: Espoma's Cactus/Citrus Mix
I also placed gravel at the bottom of the pot to "Improve" drainage, but it also has holes at the bottom so I was unsure if that was really needed.