Why me, unisom for nausea.

So from I think 10w pregnant to 18w I took 50mg unisom, every night. I cut it out cold Turkey n now I have palpitations and sometimes a rapid heart beat. Is that normal to withdrawal from something fir taking daily? Most days I took 50mg, some I took 25mg. Ive seen some girls take 100mg a day n they have no problems when they stop the unisom. Will these side effects eventually wear off?

I took unisom for HG, i had it severely.