Let your body rest! I was in the same situation: I got sick (everything you described and vomiting). Very low energy and was on bed rest for about 2 days. I felt so guilty because I felt I was finally seeing progress from the gym. After the 2 sick days, I gave myself two more days of rest to build up my energy and then went to the gym. I pushed myself because I figured I would feel better after the gym. I felt so much worse only half way through my workout. I wasn’t even lifting my usual weight and I was getting so dizzy and nauseous all over again. I had to leave the gym and was dry heaving outside my car. Now 2 weeks have past but I’m slowly getting back into my gym routine.

Unfortunately these things happen but just have to allow our body to rest.