High risk and working?

So im planning a pregnancy. But I was high risk during my last pregnancy and more than likely will be high risk this time. I've been at my job for a year and 3 months. During my last pregnancy i wasnt working so i was free to go to my appointments at whatever time they wanted me to be there. But now i am working and idk how it will work. In my first trimester they wanted to see me every week. Then my second trimester every two weeks *they eased up on me* but my third trimester i was getting seen twice or maybe 3x a week. So im not sure how this is going to work. My boss always says she need people who can come to work and we're always short. Just wanting to know can she fire me because of me being out so much? Im not sure. I put in a year's worth so im hoping that counts for something and is not a big issue towards me being out. Its to the point where me and my boyfriend is kind of willing to wait out on this whole pregnancy thing.