Not according to the maths unless your are unlucky. Of course some sessions you will loose, some you will win, it is the delta's that matter. Try it yourself on a free blackjack table with dummy money. But you will need to average it out over several sessions.
I ask for a private table to play £20- £500 hands and don't touch the newbie £2 tables. I leave if another player who doesn't know what they are doing joins, which is rare, as I like a brisk game. I usually start of at £20 stakes and depending on the night might endup around the £100 - £200 mark.
This is not a perfect strategy, it is a basic set of rules to play to put the odds statisitcally in your favour and is independent of other hands. (Of course other hands affect cards, but it doesn't affect the thinking process of these rules)
Also the rules are extremely simple to follow without complex mind numbing calcs and not outrlawed by the casino's. Infact at my regular casino I may as well not be sitting at the table as the dealers know how I play perfectly everytime.
That said, no stategy is perfect otherwise blackjack and casino's wouldn't exist.
This is my method of playing BJ over 2 years and works for me. Of course you could always try card counting
Good luck at the table.
gjrc is correct - you will lose money over time, very much according to the maths.
I'm glad your strategy is working for you, but please do not think that the odds are in your favour. If you are playing perfect basic strategy (no counting) then the best you can hope to do is to have the odds 0.5% against you - i.e. on average a 50p loss for each £100 hand. Your strategy sounds inferior to perfect basic strategy so I would expect a higher loss rate.
The only way to shift the odds in your favour is if you have prior knowledge of the cards that will next come out of the shoe - i.e. counting cards or cheating.
As humans we are prone to numerous biases and one of those is assigning outsized probabilities to favourable outcomes - i.e. you recall the times you win big, but not all the losses!