I took a Plan B pill but threw up less than 30 minutes later but I didnt see the pill?

If you were or are fertile, then you are better going for the other emergency pill called Ella (Ulipristal Acetate), as it's proven to work in more ways than Plan B.

Yes i did less than two hours I vomited but i didnt see the pill at all does that matter?

Doesn't matter if you saw the pill or not. The pill may have been broken down but still not absorbed, hence them saying to take another dose if you vomit within 2 hours. Is it worth the risk?
If you were ovulating, I advise the other pill, Ella, instead.

Okay thank you ill go get it right now

You're welcome.
You have up to 5 days/120 hours to use Ella, & only 3 days/72 hours to use Plan B, from the time of sex.
Plan B works by delaying your ovulation until the sperm leaves your body. If you're already ovulating then it may not work for you, & that's when I suggest you go for the other pill. Some think Plan B works in other ways, & indeed it might, but they are not proven, so the Manufacturer does not claim that. They are proven with Ella.
Both pills are more effective the sooner you take them after sex.

Is there still a risk even after i have taken the ella pill and if so how long will take for me to know when im pregnant

Oh yes, emergency contraception is not guaranteed to work, it's just worth a try in an emergency.

I can't really tell you when you'll know for definite whether you're pregnant or not. A pregnancy test at the time your next period should start, may tell you, if it's an early response pregnancy test, but pregnancy does not always show up in the early stages.

I recommend a pregnancy test even if you get some bleeding, as it may not be a true period, & could be from Ella. Also, some women have what they think are periods in the early stages of their pregnancies. We see that on this site.

If you normally use regular hormonal birth control, you'll have to use additional contraception until the end of your current menstrual cycle (menstrual cycle, not period) (whenever would have been the end, had you not used Ella). Ella can make regular hormonal contraception fail.