I'm not clear if you mean that you put it into the fridge after a total of 48 hours. If that's the case, I think it was far too soon. If you kept it out longer than that during the activation process, let us know. One thing I always do is feed the starter and leave it out for 60-90 minutes before putting it back into the refrigerator.
If I were you, I would take a couple of tablespoons of the starter, and go through the process I described in my last post, keeping it out of the refrigerator for around 3-4 days while you build it back up with smaller feedings and then discarding and feeding on the schedule I suggested (others may have a different take on it, but it seems to work).
I don't really need to manage my starter because I use it 2-3 times a week. I pull it out of the refrigerator, let it come to room temperature, discard around 1/3 cup, and feed it with 1/3 cup of flour and an equal amount of warmed (testing it on my wrist so that it isn't too warm) water (by weight, which I can now do by sight). If it seems a little off when I mix it with my whisk, I'll adjust either the flour or water. I then keep it at mid-70s, and in 4-6 hours, it has doubled to tripled, and is ready to use.
When I was using it less frequently, sometimes I would find that I was getting a smell that was too alcoholic, so I would discard all but a couple of tablespoons of starter and feed it with more flour/water until I got it back to a less sour state.
Hope that helps.