It doesn't sound like the same thing, mine is like butterflies - for instance when you like somebody and your stomach does a massive turn.........this happens all the time, even inbed. I don't think it's gas.
I have not ever taken Lexapro, so I don't really know, I would think that being on it only 7 days however would not give you this reaction. Ask the pharmacist, he should be able to help.
I have "stomach flips" I actually discovered, for me, they are gas bubbles causing my heart to do the "flip flops" they are called PAC's or PVC's and are usually benign, but they are very annoying. Lots of folks that are nervous have them. Next time you feel a "flip" try to feel your pulse too, if it feels like it is skipping, it is just a nervous heart reaction, more than likely due to gas. Try some Tums or taking a good digestive aid, maybe this will help those "flips"