Constantly feel ill is this normal?

I need some advice/reassurance. I'm around 7 weeks pregnan ( I say around as apps are estimating different to what my midwife said) and I feel absolutely shocking. I wake up on a morning and I don't feel too bad but not well enough to eat anything. I work full time and as soon as I get to work (been awake around an hour by then) I feel so nauseous. My stomach churns I daren't eat anything hardly all day because I've been suffering really badly with diarrhea. I have dodgy bowels anyway so that's no shock, but I feel nauseous all the time and not actually being sick. I daren't eat anything incase I am sick because I'm trying to hide it from people at work until I know everything is okay. Around 3 hours into my working tired I hit this extreme tiredness and can't stop yawning. My boss has started to notice but I can't help it! On top of that I've been getting stomach cramps not too painful but can be quite uncomfortable. I know these symptoms are all normal but how on earth do you get through this and hide it well when you work full time?!?! Once I'm home my symptoms don't ease much but at least I'm in the comfort of my own home and around people that know about the pregnancy.  Need some tips please or some advice on things that may help.