I was enjoying the FE scinario/campaign and at some point on the second map, my hero's got multiplied?

I did not notice until after i fought the dragon several times reloading until no one died then i got the combat report list and thought "WTF" Who the hell are all these fallen heros and how come i did not see them get killed??

I ended up with three pages of hero's, each individual replicated up to three times except the soverign

I did have an earlier save which i kept after i fought the dragon the first time round and there was only two pages of heros.

Also i noticed that when i reloaded the game to fight the dragon again, my manna has gone down to the point after fighting the dragon, "WTF"??? But it is a saved game??

Also i think i may have had extra hero's added at some earlier point in that second map, because all of a sudden my hero's stopped gaining levels normally while i was fighting hundreds of armies floating around.

i have started the whole campaign over again, because i cannot split out all the extra heros and it is going to be too hard to get experience upgrades with all those experience suckers hanging on!

EDIT:

After writing the above post, i came up with an idea!

What if i always restart the game first before loading a save, will that fix the problem?

Also i could Possibly create two saves, so the game can play around with the most recent save when i exit the game, but i never load from the most recent save? The most recent save being the 'sacrificial' save, will that work?