Have any of you had to phone in sick for work yet due to pregnancy related issues?

I am literally so exhausted I feel like I'm going to crack soon I'm basically coming in from work at 4pm napping eating and going to bed but it doesn't seem to matter how much sleep I'm getting I can hardly keep my eyes open I get so tired I can feel my pulse everywhere and feel like I'm rocking/swaying with every heartbeat 😩 I've told my boss I'm pregnant a who few weeks ago who has been amazingly lovely about it all let me loads of time off for all my appointments etc but I've only worked there a month and found out I was pregnant on the morning of my 3rd day so I'm really worried to call in sick I want to make a good impression still😥 I'm not going to affect anybody's work loads by being off either as I'm only training.

Just need some advice is it a legit reason to phone in for being tired!? I feel so stupid but I don't know how much longer I can do it for.

*update* I had to phone in sick in the end because I was so exhausted I collapsed and came around 10 minutes later! I have booked an emergency appointment at the doctors to check my BP and iron levels

And for all the comments below I have now slept for more than 16 hours and I'm still exhausted there were no more hours in the day I could get more sleep unless I don't go to work, like today.