I saw my java was a bit outdated so I removed it from my pc. then I restarted my pc. then I downloaded the latest version of java to my pc. I installed, checked if everything was ok by letting the java website do some tests and restarted my pc again. now when I press play online in the launcher it says.
Error: could not create the java virtual machine
Error: a fatal exception has occured, program will exit.

So either this is a problem with mc,
a problem with java,
or I'm doing something completely wrong. (<-- probaply this one)

Thanks