Well, mixing medication's unpredictable period, but it's also really hard to say because...well, here's the thing. All those times you took 15+ Tylenol and it did nothing? It didn't do nothing.
Acetaminophen isn't a drug that causes instant death like a lot of people seem to think. you could take the whole blasted bottle at once and it wouldn't kill you....that night.
Acetaminophen causes severe liver damage, but it can take several days to do the damage. Now, granted, the liver is a strong organ ad it heals over time, but we don't know what shape yours is in after all those overdoses. It's actually fairly surprising that you didn't end up in the hospital with the severe abdominal pains that indicate liver damage. And so it's hard to say how much more abuse yours can take....it's also worth saying that death by liver failure? Not a fun or quick way to die. Purportedly very painful.
All that said, taking just one of the drugs you have probably won't hurt you...5 benadryl will make most people sleep like a rock for a good 12-15 hours, but wake up fine but groggy.
A dicyclomine by itself shouldn't hurt you either, assuming it's actually yours. It's using to treat IBS.
6 regular ibuprofen
Here's the thing. Chucking back random cocktails of pills will, more often than not, just land you in a hospital for a while. You might be unlucky enough to have organ damage, which would be painful and expensive. But if you're going for a "cry for help to see if anyone cares" kind of thing, there are definitely alternatives that don't involve doing stupid things like chocking back whatever pills are lying around. Because the fact is you don't know what they're going to do. No one does. And most of the time, they're not going to kill you painlessly; they're going to land you in chronic pain or possibly with super-high medical bills. If you're looking for a "suicidal gesture" type thing, it's much more solid to find a therapist, teacher, or just good friend to actually talk to, rather than just randomly taking crap to see what happens.