Is there any difference between generic and name brand Paxil CR?

Ok i have been takin Paxil cr 25mg (generic)for anxiety/depression. 1st of all it makes me want to sleep all the time, and second when it is almost time for my next dose I experience a little bit of a different heartbeat, usually a little faster off and on, then I get a headache (every day) on the left side of my head that I can actually feel coming on from the time I get out of bed. Can this be from the Paxil? Sometimes I can't help but wonder if there is some underlying issue going on with my heart, but I think it might be the Paxil CR. Before this med I took the name brand and I don't remember feeling this way. Is there a difference between the name brand and the generic Paxil CR? I have to take the generic because I don't have insurance now.