hey there
these are all normal feelings so don't think you are being selfish or ungrateful at their enthusiasm... i can remember people saying that my MIL was waiting for us to go out for the evening so she could babysit DD, and this was at SIX WEEKS!! i was in such a poor physical and emotional state for months after the arrival of my girl that it really stressed me out having people impatiently waiting to babysit her... she is now approaching two and still my MIL has never had her overnight... she rubbed me up the wrong way early on and it made me COMPLETLEY back away, and now as time has passed my dd is just way more comfy with my parents when it comes time for sleep overs etc...

anyways i just wanted to say, in relation to them always holding him or putting him to bed etc etc, please please please don't be afraid to say 'i'm going to take him and get him settled for bed now' or 'he wants his mummy' or 'time to hand him back' all with a gentle smile on your face.... he's your bubba and when its your first for some reason you lack the confidence and somehow well meaning relatives seem to take over, against your will... you've got to get more vocal as i bet a million dollars they don't realise how it makes you feel... there is nothing wrong with gently saying its time for him to return to his mummy etc.....

in regards to babysitting i would just smile and say 'no way am i ready to be away from him yet, i'll get back to you when he's 2!!'.... i think as long as you appear light hearted and gentle there are ways to subtley give them the hint that they'll be waiting a while... also if you are breast feeding this is an excellent excuse for not handing him over for babysitting...

id be claiming my weekends back too... be creative and think of some reasons to be at home... can you join a mothers group and then say you have plans to catch up with them (even when you don't)... can you say you're tired and just want some quiet time with your bubs?

start with baby steps in regards to gently asserting yourself and then work up... don't be afraid to say you're not up to visiting or just not feeling like it, you are a new mum and have the right to be tired and not in the mood for visits etc...

ps next time i have a little one i'm making a sign for the front door each time i don't want anyone visiting... as simple and rude as that!!