example: i was at work today and i felt high, like typical symptoms but i haven't smoked weed in like a week or something like that.
I felt relaxed, sleepy and shit was funny to me that usually isn't.
could it be that it is in my veins/system like nicotine stays in the smokers system and it kicked in?
No, but it could easily be residual cannabinoids still attached to your brain. Weed gets you high primarily by binding THC and other cannabinoids to special receptors on your brain; over time the majority of the THC breaks off and you come down, but the rest can linger for a little bit. If you smoke a large amount this can cause you to feel some effects of pot without smoking, because on some level you're still very slightly stoned. It's entirely possible that you still had/ have some cannabinoids attached to receptors on your brain (for heavy smokers they can take up to a month of not smoking to be fully cleaned out), and that this is what was causing you to feel unusual.
Maybe you just haven't slept enough.
I got enough sleep last night. My usual 8 hour sleep.