Work, dilemma..need guidance

So I work with supported living (complex needs) i am still on probationary period. I rang in sick today as i was going dizzy, sick and diarrohea. I am 16 weeks 5 days pregnant. So this could be pregnant related or a bug etc. Anyway the manager expects me back tomorrow but i move a little and dizziness starts. When im sat down im fine. Its when i stand and walk. Ive not been sick in a few hours but got belly ache. It will take me 20 minutes just to walk to work tomorrow. Im scared to say i cant do tomorrow because im still new and relying on this job. With me been in probation it doesnt look good having sick days after a month. Little things like this work me up. Just need a little input on what would you do!!!