Food...uggh

So I'm 16 weeks pregs and Iv had 2 episodes of fainting or feeling faint. 1st trimester I could eat anything and everything and now in 2nd trimester I find I'm struggling. Today however I have felt so off my food! I'm simply struggling to eat anything, also had to get off the bus and go lie down on the grass cause I was just too fainty to stand up or sit down. I haven't felt right all day. Just after some feedback should I be worried. Iv just tried to force a healthy cottage pie down me and really struggled. Got just over half down me n just feel yuck and Weak. Not sure to be worried or just accept I'm having an off day. Can't help but worry my lil baba is okay