You are running on empty this is why your body is suffering. I have dropped 60 pound of my baby weight in 5 months, im almost as thin as when i got married and i have 2 kids.

Listen, eat 1600-1800 calories, try a less strenous exercise on your knees. Try doing elliptical at your gym and doing step machine. You might have pallateal knee too like i did, put some icy cold rub on your knee, apply ice and heat. Take some pain killer, and also rest your knees for a few days or even a week, nothing will happen they probably just need repair. This is my eatting plan ok look

Morning

2 eggs, with slice of toast and skim milk

midmorning snack- protein shake

lunch- protein, salad, carb

afternoon snack yougurt or fruit ( orange is best- burns fat!!!)

( Gym 1 hour 20 min alternate days with weights, and abs everyday)

dinners

bedtime snack ( some cereal or something light ( almonds, whatever)

I also take 1-2 days off for rest

Don't injure your knees so much that they will hurt you for life!

Take it easy, and see if it gets better, if they don't than i suggest you need to go to

a physiotherapist and look if anything is damaged your tendons or nerves!!!!

The reason you feel ill is because your body is starving honey! You need fuel, if you want more weightloss learn how to eat first!

Abs, muscle dont form when you dont eat! They form when you eat the right things, and you give them the best and challenging exercises 80% is diet 20% is exercise you cant have one without the other.

I never do more than 40 minutes of cardio ever! After 40 min your body just depletes your energy storage not your fat! When you do high intensity in a short amount of time after 20 min, your body starts to burn the fat! I do this and I do only how much i can handle and than after this I do abs, or weights.

Do weights, strength training, the more muscle you get the more your fat cells will shrink and your body will burn fat even when you sleep, no joke i love weights now and its good for bones too because it makes them stronger, like your knees!.

feed, heal, love yourself and everything will be ok. be proud you lost so much weight, and your on the way to a new you. cheers