I'm gonna take an opposite stance by saying no the thoughts shouldn't scare you.
Does being alive make you happy? No not really you're just alive and don't really get HAPPY about it.
Death after all is just as natural as being alive. Freuds the one who intially said people always have a survival instinct and death instinct naturally oscillating through most of their life so I believe its perfectly normal to contemplate death.
People fantasize about how their relatives would act, how bad they would actually be hurt, and what kind of impact their death in general would have.
When you're depressed its just as normal to go over rituals in your head of how to kill yourself.
I mean at one point in my life I think I did this everyday for a couple years straight and it actually became an OUTLET to not kill myself. For some reason by thinking about death it does liberate you a bit from depression knowing there IS an escape.
Most people ethically don't support suicide, niether do I, but I still think what you're doing is completely normal and that a shrink would tell you the same thing. I do also agree with others that the particular method you're contemplating WOULD be a TERRIBLE way to go out. So the fact that you've haven't thought it out that much to understand it would in fact be painful shows me you haven't really thought THAT MUCH about it.
I think anyone who was seconds away from suicide would have figured out that allergic reactions would be the last on the list to pick in terms of comfort. Since there are so many common sensical painless ways to die I'll refrain from talking about that either.
I don't think this thread mirrors intent and I just want the OP to be comfortable with his thoughts even if they ARE about suicide. Only because it was so natural for me to think about myself and for whatever reason I think being able to think about it actually helped me in the long run rather than being scared of an idea that hasn't happened yet.
Good luck and all I can say is on a long enough timeline for most people life IS worth living. Just that people seem to have an easier ability to remember bad memories over good ones. And I think its becauses humans are innately somewhat selfish and just EXPECT good things to happen. When bad things happen we feel wronged, but we never realize thats the literal price you pay to enjoy the sweet things in life.
If we didn't have those extreme lows in life by contrast we wouldn't value the extreme highs to the extent we do. If you just went through your life getting smacks on the back of the hand everytime something terrible was suppose to happen then when something real good happened you wouldn't even appreciate it.
Thats the balance of life I guess.