Aww :hugs: hun i could have written almost this exact same thing a few days ago.
Both my girls are teething and DD2 has been a nightmare to get to sleep, i have been trying to get her to sleep in our room as i want her used to sleeping in a quiet room.
So DD1 follows me everywhere, SISTER, ZARA... MUM, MUM, MUM then right as i finally get DD2 to sleeo after 45min DD1 comes in SCREAMING and LAUGHING MUM, MUM, MUM and pats DD1 on the head...

I LOST IT. plopped DD2 on the bed, grabbed DD1 and SCREAMED at her, get out, get out, get out... stormed her to the lunge forced her into the corner of the couch and yelled again not to move until i tell her.
I was so ashamed of myself, i went and sat with DD2 until i got her to sleep and then went out and cuddled DD1 for about 15min while we both sobbed.. i have NEVER done anything like that before and highly doubt i will again... i was so so upset.
Although DD1 didn't move from that couch until i come got her... shame she doesn't listen so well all the time.

Please don't be too hard on yourself, even the most perfect of people will do it at some stage, hope your DS is better soon and your back to getting some sleep.