improving cardio questions

Been training for about 4 months now, came back from a 6 month layoff from knee surgery. My cardio has been sucking camel dick. I train 2-4 days of jitz a week depending on if I have exams. On days that I don't to jui-jitsu I run at least 3 miles at low-medium intensity and lift weights (2-4 hours before I run and eat a meal in between).

I'm throwing up in practice and I'm sick of it. I want my cardio. Help?

Consistency is the key. Keep at it. It will happen.

Research and try High intensity interval training (HIIT)

I found that doing sprint HIIT really helped to take my cardio to another level and what's great it that it takes so much less time to do it compared to traditional cardio stuff. I get easily bored on the treadmill.

yes I've been doing combinations of HIIT and LSD training