Workout too hard?

I just started Jillian Michaels kickboxing and I love it! I really enjoy doing and just did the 2nd workout today. It was hard but I still made it through it and did good. My only concern is afterwards I feel real shaky and a little lightheaded with a slight headache afterward (the headache is gone now, was just right after) ? I have pre hypertension which is my main worry. I didn't feel like I was over doing it though while doing the video. I'm not trying to sound like a wuss or something, I'm very serious about working out, I just want to be careful. I have lost 16 pounds so far and am now 264 from 280 and have just the past two days increased the intensity of my workouts.

make sure you're eating enough protein to get you through your workouts a few hours before

Eat within a couple of hours before your workout and make sure you're plenty hydrated!

Sounds like you're not eating enough.

I don't think i drink enough today before I worked out. I'll have to keep that in mind.

How much protein should you have before a workout?

I had a late meal today around 1:00 which was a 6 inch sub and Caesar salad - 810 calories, started the workout around 5:40 maybe? I haven't even felt like eating lunch so maybe it's how little calories I had before?

I usually eat around 1600 a day but if I eat a late breakfast/lunch I'm not hungry the rest of the day so I haven't worked that in yet. I had doctors appointments today so didn't have time to eat this morning.

maybe try some grilled chicken breast. I've heard anywhere from like half a gram to 1 gram of protein per pound of body weight but that's a lot to me. I eat a lot of eggs, greek yogurt, and chicken breast to keep my protein and energy levels up. You could always make a smoothie with greek yogurt (plain), milk, a banana, and some mixed berries an hour or so before you workout. You can throw in some flaxseeds or whey protein too but they have a higher calorie content.