Leaf loss is pretty normal for this plant, especially when it changes environment. Two months isn't that long, so it could still be in an adjustment phase after being transported from Ikea. But it depends a bit on how the rest of the plant is doing: are the leaves that are falling dry and shriveled, or do they drop while still firm? And do you notice if the plant is still putting out new growth, or does it seem completely stagnant?
The critical issue is almost always air humidity. String of pearls loves humid environments, and if you keep it in a house with heating or dry air, it tends to lose leaves even if watering is technically correct. Try putting it on a tray with some water (without the pot touching the water directly) or mist it every now and then. Indirect light is fine, so that's not the problem.
One more thing: check that the soil is actually well-draining. If it holds too much moisture, the roots suffer and the plant reacts this way. This succulent needs a light mix, like cactus soil or enriched with perlite. If overall the plant isn't black or soft at the base (signs of rot), it's probably just a matter of adjustment and humidity.