Should I just not play on-line?

[PokerCad]

OK I'll admit it, I am a B&M player, But can anyone help me with this dilema? How come I can sit for 20-30 hours a week in my local B&M playing 9-18 thru 20-40 depending on my moods track all of my play win month after month, deal with the swings of up 2K, down 2K and such, just the normal variance, feel pretty confident that I am one of the better players, tho admittedly I still think I suck in terms of the truly good players (but that is for another post, I still struggle with known gaps in my play) but my win rate is satisfactory at these limits, but anyway I can get up after a poor night say down 1K or so and not have it bother me as I am able to look at my live play as one long session. However when I play on-line ring usually after playing a MTT (oh, by-the-way they do suck but it is fun to get lucky which I do occasionally) sorry 'bout the ramble, but why do I get so pissed off at myself dropping a hundred bucks at 3-6 online? I can play for weeks live and think I am a decent player, and within a couple of hours at the friggin' low limit online game I begin to think I really suck and it takes me hours to recover mentally. Any advice??????

PS: Advice different than telling me that I do really Suck, lol