Is it possible to get pregnant this way?

Ok. So right off the bat, I believe I suffer from serious anxiety/worry/hypochondriasis issues. I always think I have some sort of medical issue, and I'm constantly looking it up online. My body even starts to mimic the symptoms sometimes.

I like to masturbate quite a bit. I'm a virgin and I've never come CLOSE to having sex... or even a boyfriend. I know mentally I couldn't handle it right now.

I live with a brother and my dad. When I masturbate, I NEVER touch my genitals with my hand/fingers. I always rub/press my clitoris over my underwear and pants. (Sorry for the details) I'd like to know how safe this is, and if there's any possibility what-so-ever of becoming pregnant this way.

Right now, I keep thinking I'm pregnant because I laid down on my brother's bed, just talking for a few minutes. Then we had dinner, and about an hour later I masturbated alone in my room. I was wearing my heavy, fuzzy, pj pants, underwear, and a pad (because I'm on my period, I wanted to ease the cramps). I don't know if my brother masturbates... he probably does because I'm sure a lot of teen boys do. There weren't any tell tale signs of semen on his bed. I checked for stains the day after. And before we talked on his bed, I know he'd been on the computer for a while so if he did masturbate on his bed, it wouldn't have been very recent. Is it possible semen went through my clothes and when I masturbated, I got pregnant?


That would make an awkward family conversation....

Like I mentioned before, I have serious worry issues. I know it's near (IS) impossible, but I HAVE to hear it from other people. I don't think I'm going to masturbate again because of the way my mind reacts.