I feel your pain love, I have awful fatigue, food aversion & nausea & I have physically been sick a few times.
Eating is a real struggle because everything smells disgusting. I was so much worse in my last pregnancy & the only food I could eat was plain cooked pasta with grated cheese & plain rice with chicken oxo cube for a little bit of flavour.
During the first trimester I just try & eat what I can without worrying about weight gain. Working on reducing weight gain can come later when the sickness has subsided & you have more energy.
Have you tried eating really plain foods little & often, stuff like wheetabix, cornflakes, super noodles, stuff that needs no or little amount of cooking, so no smell to put you off.
I also find moving around a little bit with rest in between makes me feel a bit better. It's hard at first because I have zero energy but if I try & do stuff round the house with frequent rests I feel much better the next day. I felt shocking on Sunday & stayed in bed most of the day. Yesterday I felt awful but I had the school run to do & my 3y/o at home to take care off so I didn't have much choice to move. I woke up this morning feeling better than yesterday so today I'm trying to do the same, move a bit with rest in between.
I hope you start feeling better soon, first tri is the worse