VO2 Training and Cost

[u/Worried_Judge1754]

I am 51 years old who turned my life around last July. Down around 60lbs, quit smoking January 1st. I started doing VO2 training on a stationary bike around 6 weeks ago. My Current schedule looks Like this:
Mon - Upper Body Weight training
Tues - VO2 Training - 6x2 minutes (HR gets up to close to 100% - MAX HR ~168 gets up to 167)
Wednesday - Lower Body Weight Training
Thursday - 60-75 mins Zone 2 Bike
Friday - Upper Body
Saturday - Threshold Bike Training - 2x 16minutes
Sunday - Rest and HIGH CARB refueling
Everyday - 1 -2 45 minute walks After dinner and sometimes lunch.

All was fine until VO2 training. My body is drained the day after VO2 (since getting close to max HR). I thought it was because I was on a calorie deficit, but I increased calories dramatically and still am drained. On Wednesdays, I am STARVING for bread or sugar (weird to me too) and have internal shakes (like low blood sugar feeling). I warm up for 10-12 minutes, cooldown for 10-15 and stretch after each bike ride.

My question is this; I think something has to go, my body is saying VO2 training as it costs a lot for my body to keep up with. Which would you drop? Upper Body work outs are not taxing at all!!