Thats how it usually goes with the androgens. You gotta feel shitty for a while at first because your body is so depleted and not used to having so much DHT. Then all of a sudden you'll feel awesome as the body adapts. i Would stick with 400 mg for a first cycle, also its a bit late to bump up the dosage at this point in the cycle. On your next cycle you can go up to 600 mg as your tolerance will have increased by then.