Aww don't get upset hon! You're not a 'target' for him, he's just playing. It's lovely that he feels so comfortable and safe with you to play on you like that. You just need to let him know what is and isn't ok that's all.
Use your voice. Don't just distract/divert. Calm but firm, low soft voice...tell him noooo! Hold out your hand in a stop sign. If he's already climbing up you, take him off you put him on the floor, look him straight in the eye and say noooo, holding out the 'stop' hand near them. Be consistent. Choose what you will and won't let him do, the pattern you set now will shape his adulthood. (not to say adult cats can't be trained to behave better but it's a lot harder.) He'll soon get the hang of what he is and isn't allowed to do. It might take a while but he'll get it. But you need to let him know what is and isn't ok.
Someone we knew thought it was cute when their kitten played at attacking their feet under the covers in bed... cut to it being an adult cat doing the same thing and they were more than annoyed - and scratched to bits!
You just gotta train them that's all. Like I said, be consistent. Tell them what they Can do too. So when he does stop, change your tone, be upbeat & happy and tell him he's a good boy. Lots of praise & enthusiasm & strokes etc (esp around the face & chin).
When he's playing with appropriate things, again, use your voice. The happy upbeat excited approval tone.
This way they gradually learn what is and isn't ok just from listening to you.
Clipping his pins will definitely help with the pain! But it won't address the behaviour.
With cats, if they are genuinely in proper angry attack mode (your little boy sounds like he's just being a normal bouncy kitten trying to play with you. Their play includes practicing hunting and pouncing lol) If you feel threatened you can use a 'staring out' strategy to assert dominance. This is what they do to each other. Be aware they may sometimes pounce on you if they feel angry enough to take you on! But this won't be an issue with a kitten! Hold their eye contact and don't break it until they do. Keep it longer still, they will look back! Keep that stare (It can take quite some time) until they soften their eyes, they may do this with long blinks, looking away, turning their head away or walking away. But keep your eyes firmly on theirs until they do. I do this with the neighbours cats when they're being bulshy in my garden lol. It tells them you are boss! It's a good technique to use on your kitty every so often, when he goes too far with regards to a more aggressive play. Or... if he gets too angry with you when you're clipping his pins ;-)
The rest of the time. Give him tons of cuddles and brushing sessions and use the positive voice then too. It all feeds into letting him know and get familiar with good things and bad things.
Regarding the loose stools... Ours has always had a funny tummy bless her. We found James Wellbeloved food to be very well tolerated by her. On the expensive side but it definitely beats cleaning poop!
Enjoy your bundle of fuzz, it'll all be ok, you'll see ;-)