I don't know if I'm having feelings for my ex again. Please help and I'll answer one of yours!?

It's not abnormal to keep an ex in our heart and still feel affection for them - this can go on for years  or for the rest of our lives.  I think of a couple of m exes very fondly, but i'm not in love with them anymore. However, i still care and this is normal. After all, we were emotionally close at one time in our lives.  There's nothing wrong with thinking of our ex; however, if a person hasn't recovered from a break up and is still all in love and emotionally attached to an ex, they really need to take the time to recover, and not rebound to someone new.  

There's a difference between feeling care for a person we used to date and being all emotionally attached.  Most of us eventually lose that emotional attachment after a break up.

Your ex isn't really relevant to the problems in your current relationship. This is a symptom of doubts you already have, and an excuse to avoid confronting them. Talk to your girlfriend about the "disconnect", figure out why you feel that way and resolve the problem together. Either things will improve, or you two will decide your relationship has run its course. In the meantime, stop talking to your ex. You know you would want your girlfriend to do the same if she felt tempted by someone else. Give your relationship your full attention.