I'm also a first-time mummy, now I'm 22wks 3days and I'm same as you, when the first few month of pregnancy I keep falling sick and having morning sickness. But I still took MC or leave to rest, but come to a point that my supervisor told me that I have to stop keep taking MC or leave cause will affect my work and also not very good nah. And also my boss ask regrading I keep taking MC or leave. So after that if I'm really not well then I will take MC or leave, if I still can make it to work then I will still go for work.
If you really feel very unwell, just take MC and rest cause we need alot alot of rest. If you think you still can go to work then just go for work norh. dont't have to afraid of taking MC or leave