Triple Study Pre-Screening Rejection

I am now in full bore trying to participate in as many trial studies as possible.  It's the only job I can find these days.  It's also the only ones that I'm really OK with.  Going to an office 40 hours a week?  Ugh.

But I've stumbled upon a rough stretch lately.  I've been on the phone three times with people representing studies.  When they've asked me questions, I've said the wrong thing and was summarily rejected:

• First time was with someone whom I talked to before for this study, actually.  It's as if she didn't recognize me from before.  How heartless.  And when I said that I took allergy medicine, I got the kibosh.  Just for allergy medicine?  And didn't I tell you this already?  This was going to pay sweet money, but I had to drink this protein shake.  I probably wasn't going to be able to hide it from my parents, whom I know would ask something like, "What the fuck is this?" and we'd get into an argument.  Actually, there was a requirement that I wake up in the morning to drink the shake.  I actually qualified the first time I spoke to this woman but balked because of that.  But I convinced myself I'd adjust my sleep schedule, or lie, to take part.  Too bad I didn't qualify the second time after qualifying the first time.  Whatever the fuck that means.
• Second time I was driving and had to literally find the closest parking lot (my local post office) to talk to her.  I had things to do that day.  She seemed nice, chatted me up, blah-blah-blah.  But then she asked me if I did any other studies at the U.  My guess was that studies at the U. talk to each other, so I came clean.  And after asking me a couple light questions -- "How's it going?  Do you like it?" -- she abruptly told me I didn't qualify.  Screw you, lady.  Man, I should've lied and said I wasn't in any other studies.  The U.'s a huge bureaucracy, she wouldn't find out.  Dammit, I should've lied.
• And the last time was a couple days ago when I was having coffee in the morning.  The pre-screening questions got real personal, unlike the others, so when they asked me if I had a certain disease I had to hope the men's room was unoccupied.  It was, but my voice echoed in it, so somebody might've heard that I had ... uh, the disease she asked me about.  I knew that she was going to cut me, but again, what if I get caught lying?  She was the nicest of the three, though.

Why can't I find a study that doesn't mind having a 33-year-old, glasses-wearing, somewhat-pudgy, sort-of-diseased, ongoing study-taking, allergy medicine-popping unemployed dude as a participant?