7 year old constantly nagging

My son has ASD, and i love him so so much, but i cant help but feel so irritatated by him all the time. Hes constantly has to be touching me, or practically on top of me, or constantly kissing my arm or leg or something. I know hes only trying to show affection but its non stop. We are going to the cinema on Thursdayto see the minecraft movie, online theres a booking fee, which just for me and him there is no point paying until we are there. I have told him we will pay and choose our seats when we get there, however he has then gone on and on and on about choosing, paying and booking online, and i mean its every 2 minutes he will have it up on my phone or the ipad waving it in my face, and he does not stop, and there is only so many times i will tell him calmly to stop and we will pay when we get there and that he can choose the seats then. Well i ended up losing the plot and confiscated both my phone and ipad and gaving him some lego to build. I feel awful but i also feel so depleted right now. And even when i try to plan something nice he is so so ungrateful and just ruins the day. Last week i took him to the beach to fly a kite, get dinner and spend some coins in the arcades and by the end of the night he tells me 'i dont like the beach remember' when just makes me feel really shitty, im a single mum with very little help and little to no support system let alone any friends or mum friends, the last year or so has just been so so hard, i just feel that no matter how hard i try its just never good enough, that im not good enough :(