I Have Been On Adderall Since About September And Then

I have been on adderall since about september and then in February i started having some heart problems and so my doctor took me off of it. After seeing a cardiologist he told me it was a flow murmur and it was fine to go back on my adderall. I am now like 5 days late on my period and there is no way I can be pregnant could it be because of my adderall?