my boyfriend left me and im 6 months pregnant

i had been with my ex just over a yr and im currently 6 months pregnant, everything between us was perfect yeah we had bad times but they were mostly down to his ex playing games with him by not letting him see his kids as long as we were together so about 3 weeks ago he asked me to marry him i said yes then he went to see his kids and when he came home he said that he couldnt keep doing this to me that he doesnt want to hurt me but he cant not see his kids and left. he has said to me that hes doing this so he concentrate on being a good dad to all 3 of his kids and so he can sort himself out, but i see it as his ex gets her way. i dont know if its so hard moving on because of all my hormones but im really struggling to let go i know it gets easier and i gotta take one day at a time but im not sleeping and when i do manage to sleep i wake up with my mind racing im stressed and i dont know what to do, my family are supportive but telling me im better off without him doesnt make me feel better, and i dont have any friends as i have 4 other children from a previous relationship and spend all my time in doors getting over this relationship is alot harder than getting over my previous relationship of 11yrs so please any advice.