I don't know about the kicked in the nut feeling....I havn't had that....My friend is on test and he said he really started to feel it around the 7th, 8th day....HE said it creeps up on you and then when it hits youll know... THat is a good cycle, I know a lot of guys doing the same thing...He is in his 6 week and has gained 11 lbs! Its crazy I see him every other week and he is so much bigger then the previous week...I told him he needs to buy some more shirts cause he is blowing out of the ones he is wearing. What is happening to you it probably that your test levels are so high right now that your body is trying to adjust to it....I have felt different feelings throughout my body the last 4 days but nothing too scary or painful...besides when I took my first shot. My arm is so much better now....dosn't hurt anymore but keep me updated