Go to an al-anon meeting. I'm dealing with a couple of alcoholic friends and was reminded that badgering, pleading, or criticizing does not influence someone who's drinking to change in any way. I'm starting with al-anon because I'm frustrated and don't know what to do with them. Their drinking negatively affects our relationships.
One of them has been my friend for over 30 years and I have set new boundaries with her so that I would feel more in control of my own life. I suggest that it may help you to decide what you are and are not willing to put up with and tell him when he's sober. For example, you can tell him that when he comes home he cannot sleep in the same bed as you. He stinks, snores, tosses around so that you don't get good sleep. I'm just guessing with that. The idea is for you to do what you have to do to take care of yourself.
Unfortunately, before I could form new boundaries with my friend, I had to emotionally distance myself from her. I had to find a way to stop caring so much about how she acted. This will be very difficult for you to do because you do live with him and are carrying his baby. But it is the only way I know of to take care of yourself and your baby.
I suggest that you find a way to be independent of him. Can you live with family or a friend? I also suggest that you get help. If you're getting state assistance you will still get that assistance when you live somewhere else. You may get more, even. If you're not getting state assistance I urge you to make an appointment and start the process of living independently from him. Being under 21 is OK. What counts towards getting assistance is that you're pregnant.
He's an alcoholic and he won't change without a very serious incentive to change. And even if he wants to change he'll need help to do so. He can get help from Alcoholics Anonymous.
You can get help thru Al-anon.
If he abuses you, verbally or physically, which is common from someone who won't stay away from bars, then you can also get help from a Domestic Violence group or shelter.
I urge you to focus on taking care of you and your baby. Your husband is focused on getting alcohol and is not supporting you in this pregnancy. You need both emotional and physical support and if you won't get it for yourself get it for your baby. Both of you deserve to have a stable and peaceful life along with support from others.