I have been tryn to concieve with my husband since 05/2011, could mirena (levonorgestrel) have left me infertile? (i had it for 3yrs)

No. If the Mirena (levonorgestrel) has been removed, it will have no lasting effect on your fertility. You should understand that it could take up to 18 months for you to conceive, even if everything is completely normal with you and your partner. It is appropriate to consider an infertility evaluation if you have not conceived after about a year of trying.
Could be. It could be, however fertility does take some time to return after use of an iud. It is also possible that you have another, more common cause of infertility, or an anatomical irregularity that is preventing you from becoming pregnant. Your doctor can evalulate you for these. In most couples, time is the best cause for infertility, and they do have successful pregnancies in the long-term.