I know this isn't helpful -I have Headspace, but I am terrible about using it. I do intend to get back into it. So hopefully, you and I could both discover this together.
I absolutely love Headspace. I used to use it every day , but I stopped using it just because life became so busy. It's my goal to get back into it. I feel like the meditation really helps me when I study or take PTs.
I like headspace. They have a huge variety of meditations and some of them are only 3 minutes. I think no matter what you use, try to meditate at least once daily to really get in the habit. That's helped me clear my mind a lot lately.