When you say 7 medium to large sized leafs I'm not quite sure how much you mean. This description is too vague to draw any conclusions, it'd be easier to assess if you could approximate a weight. Even then though, I couldn't tell you if you took a dangerous amount because I don't know how potent your strain is. It could give an indication of how bad your situation could have been, however.
Nicotiana rustica has been assayed at up to 18% nicotine. Not 0.18, not 1.8, 18%. [1] Also read about samples around the 5% threshold, but I wouldn't ever presume it's a weaker strain unless you have experience or reliable knowledge.
Nicotine is toxic to people. Fatally so. As are some of it's related alkaloids like anabasine and nornicotine. There are also smaller amounts of other toxic pyridine alkaloids. [2] Toxic enough that that dozens, probably even hundreds, of children die every year from eating cigarettes. Rarely you even hear of adults, and even whole families, who misidentify tobacco plants as vegetables and cause deaths as a result. [3] These examples are all in regards to N. tabaccum and N. glauca, which are much weaker strains than rustica.
As for how toxic or deadly your brew could have been? It's hard to say. I just had a 15 minute look around on people who have died from Nicotiana consumption, the vast majority of which are scant on details, especially in regards to how much was consumed. The only reference I could find with an amount declared states that a 60 year old male ingested 10-12 fried leaves. Within 3 hours, his symptoms had gone from vomiting, severe sweating, fever and diarrhea and progressed to severe muscle weakness in his whole body and eventually smooth muscle paralysis. [4] He recovered, but bear in mind this was with Nicotiana glauca, not Rustica. By weight, the rustica could have been in excess of 4x more potent than what the glauca would have been.
So to sum up? Yeah man, that's really damn dangerous and you should never, ever mess with plants you don't understand. Especially not ones commonly used as pesticides. The shamans who practised these ancient yage admixtures were doing this literally since their late childhood. Their tolerances were out of this world and leagues beyond yours and mine; many of them were regularly consuming Rustica from a young age. Trying to replicate those feats is foolhardy at best and downright deadly at worst. Even in experienced ritual settings shamans could even die to their own brews. No need to relearn what they sacrificed for us already.
"The effects that tobacco produces among the Warao people include the following: dreamlike and chromatic visions, multi-sensory perception, brilliant occurrences of light, intuitive knowledge and spontaneous insights, soul-escort by a psychopomp, and tunnel experiences. However, these experiences seem only to happen to initiated shamans, and normal individuals consuming the same dose will often experience very toxic effects. Deaths are not unheard of." [5]
[1] (Neurotoxic Plants - Brent Furbee, in Clinical Neurotoxicology, 2009)
[2] (Ratsch 1998, 379)
[3] (Nicotiana glauca Intoxication - Two Cases in One Family, J Med Toxicol. 2011 Mar; 7(1): 47–51)
[4] (Mellick LB, Makowski T, Mellick GA, Borger R., Neuromuscular blockade after ingestion of tree tobacco, Ann Emerg Med. 1999;34:101–104)
[5] (Wilbert 1972)