Suggest Suitable Medication For Insomnia

Hi I was prescribed zopiclone for insomnia which I took for a week. It wasn't working well so I asked my doctor to prescibe something stronger. She gave my 20mg of elavil / night. It still isn't very effective but also it is making my heart act funny: big hard beats out of nowhere etc. It's freaking me out a bit. My question is would it be okay to drop the elavil tonight ad use the zopiclone again? Is there any strange risk of just dropping the elevil given that I've only used it for 5 nights?