Constant nausea- please help!

I am CONSTANTLY feeling nauseas. I can’t eat anything without feeling really sick. I’ve tried ginger nuts and plain digestives, they don’t help. I’m drinking pineapple juice which seems to work for a little while and banana milkshake seems to be doing well too but I haven’t found any food yet. Ready salted crisps were working but that’s stopped now. I don’t know what else to do! I’m SO hungry but whatever I eat I feel like I’m going to bring back up again. I ate a mouthful of toast this morning and brought it back up. Any advice ladies? Thanks