I wear contact lenses ( monthly disposable )...

I have a feeling that I have the wrong lens in the wrong eye 
( as I wasn't careful to make sure they go into the correct side of the lens
case of right/left)

My prescriptions are similar but not the same..
( so, am not able to figure out even after wearing them...)

Is there a way out to figure the power of contact lenses without
taking this to an optometrist..
is there anything out there in the market that could read the power of lens? 

Note:
Please don't tell me to dispose this one and open a new pair..  
I have been doing this almost twice a month!!!!

Thanks,
Comments are welcome..

I don't think you're going to find a device for home use that can read
the prescriptions of contact lenses. If this is a frequent problem,
you may want to get lenses that are marked. A friend of mine who wears
contacts has the right lens marked with a tiny black dot. It doesn't
show when he's wearing the lenses, but it helps him to distinguish the
right lens from the left during handling.

Try the left lens in both eyes and then try the right lens in both eyes.

If they're similar, why does it matter which eye they're in? If you
really need to see, close one eye and look at something from afar (or
kind of afar) like, put a book in front of you and try reading it a
bit with one eye, and do the same with another page with another eye.
If you were able to do it with both eyes, do the same thing again, but
take a step or two away from the book. Try reading it again, and do it
again (alternating eyes) and once one eye stops being able to read it,
that's your weak eye, now go to your box or whatever, and whichever is
the lowest number (or highest, I forgot) is the lense for the weak
eye. You can also do this with a TV or computer or something, you
choose.

Usually when you buy dispsable lenses they mark the box as to which
lense goes into which eye, if you feel that you accidently inserted
the lenses into the wrong and cannot tell a difference then just wait
till your 2 weeks is up and put in frersh ones, making sure you put
them in correctly.