Could lose job for being sick

So I am 25 weeks pregnant and I have been very sick this past two weeks. I have a very bad cough which is making me throw up constantly and choking on my cough. I went to the doctor on Monday and they took me off work until today. I was supposed to go back to work today but I am still really sick and still coughing so I called in. Now they are telling me that I could lose my job because I am out of pto now. I had like 15 hours left before this week. They are also tellingme that I am not allowed to leave work for my doctor's appointments. I work with infants 0 to 3. I cant go to work sick when I literally cannot go ten minutes without coughing and choking. I am just so frustrated because i feel like I am being targeted. When other people have missed 3 or 4 days straight this week as well and I had a doctor's not telling me to stay home.***********Edit Hr is the one who is saying i might lose my job because I didnt have any pto to use. And becauseI missed the whole week last week I am negative pto. They are saying because I used it all I will have to pay them back and I wont receive any pto at all next year when it resets. And they are ubsure if I will be able to keep my job**** edit I was fired. They waited ubtil the end of the day so Icould cover for someone who called in how ironic