Since my son was born he would sleep in bed with us or in his swing and now that I'm pregnant and we…

Since my son was born he would sleep in bed with us or in his swing and now that I'm pregnant and we don't all fit on the bed I decided to put him in his crib well he took a nap there for 1hr. and 30 mins. and now I put him down for bed and he doesn't want to stay it's hurting me alot because he was crying. This is harder than I thought but it has to be done.