I don’t know what to do?

Perhaps you could try to convince Mom to meet with this guy one on one to iron out their differences. But barring that...if you're not in the position to move out and pay for your own education all anyone can tell you is that an education is for life while a love interest you have at 19 almost certainly won't be the person you grow old with. 

Unfortunately, this is a point that many of us reach in life. If you can't reach your parents with your opinion, you are going to have to either keep sneaking around or choose. I almost eloped with my first boyfriend for similar reasons and my parents almost threw me (at 20 years old) in a mental institution. I ended up eloping with my boyfriend's best friend to avoid my parents. The marriage has been rough and sometimes I regret it. So put a lot of thought into it to make sure you choose what is most important to you. If your education is most important, then your boyfriend should be willing to wait until you are financially independent and your parents' opinions don't matter. Don't feel bad about sneaking out behind their backs though. It is your life your choices and don't let them drive you to do something you will regret. 

maybe you should move out if youre living with her

Your mother is dead wrong and your father is the only one with a mature common sense outlook.  Your life, your choices.  He's right.  

Sometimes parents see that which their child is not willing to see. 

I suppose you either listen to your mother, whom is most likely wiser, and appreciate that she wants more for you,  or simply let her know that your standards are lower than hers and you don't mind disappointing them.

Note: Your father may really agree with your mother but is aware that if he lets that be known, to you especially, then it will most likely just drive you further away, into the arms of someone they don't want to be a part of your family.

Sometimes people need to make their own mistakes.

Your mom's mental health issues are her own. Live your life,'

maybe you should move out

I think that what you need to work on doing is changing your mom's perception of your boyfriend. Every mom worries about whether the guy who her daughter is taking is looking after her. At present, she feels that your boyfriend is making you unhappy. Hence, what you need to do is to show her things have changed and that you have both become emotionally mature. The way that you can present this to her is by showing her that every relationship has its share of good times and bad. 

The other thing that I would recommend doing is having your boyfriend engage with you parents and make conversation with them. Not only does this show your parents respect but it will also make them feel that your boyfriend wants to be a part of the family and not simply take you away from you parents. Family is really important and a lot of parents worry that they will not see their kids as much when they enter into a relationship. Hence, showing your parents that you intend to be a part of their lives still will help relax them.