child goes threw four stages in the womb of the mother, the last of which is that allah gives a ruh to the child and and the angel writes four things for the baby

it is narrated in a hadith that an nabi(saw) said that the child goes threw four stages in the womb of the mother, the last of which is that allah gives  a ruh to the child and  and the angel writes four things for the baby. my question is if the ruh is not given to the child until the forth month then how can the doctors here a heart beat for the child when it is three months. also,  when we are instructed to go out in the path of allah, and told to make the sacrifice, if i sit at home and prepare and make arrangements with job and save money for family and like this then what time of sacrifice is that. i went forty days cache while not knowing  how the rent is going to get paid and not giving job a notice and also wife is four months pregnant and i was repremanded for  doing this by tashkeel brothers but why. i made the sacrifice for deen. please advise