Absolutely cannot trip on 840mg

I used to take DXM more frequently than I do now, I would usually do about 420mg 2-3 times a month. I decided after a few months with no DXM to try 840mg. 3 times nothing happened because I ate a lot before each time, but the last time I ate today was 7am and I took the DXM at 9. I got really nauseous about 20 mins ago at 11pm and threw up a little. I feel a tad dizzy but nothing crazy. I thought throwing up would just kill the high but everywhere I look seems to say that as long as it's been in your system a few hours throwing up won't effect the high.