Baby won't sleep

OK so I bath my lo (15 weeks) at 7 till half 7 he has a bottle 8 and is in bed for half 8, he will settle down with a dummy and drift off to sleep. So I put the monitor on and his night light, but everytime he does go to sleep he wakes up screaming because his dummy has fallen out or he just wants me, I'm up and down the stairs about 9/10 times in the night because of his screaming X so any way to help him stay asleep once he does drift of the first time, he is swaddled as he likes the comfort and also has a mobile above to help him sleep which I'm constantly putting on, why won't he go to sleep till he cries himself to sleep because he is that tired after screaming :(