I had blood in my vomit. I think I may have been spiked. Should I seek help?

Probably so. Two issues here: blood in the vomit is usually from relatively minor causes like a small tear (mallory-weiss), or irritation; however, it may be the prelude to or a sign of a more serious problem such as an ulcer. Your age and other issues are important too. The other issue is a fear of being spiked, so this suggests a need to assess "friends", situations and behavior choices to minimize risks.