SO problems

Ok so, me and my SO have been trying to have a baby for quite some time now and it turns out that I did in fact conceive a baby this past month (I found out on Wednesday and I am so excited) but my SO just told me he is worried about this financially (he has a great job and making about 70k a year and I have a decent job making 35k a year so I don't understand the problem) he never once told me he is excited about this for us or anything and this morning he was yelling at me and trying to start a fight about this. I am so hurt by this! I don't know what to do! If any lady has any advice for me I would be forever thankful! (He has a 9 year old too so it's not his first rodeo) are my hormones just getting the best of me or what?!