It may be that your DM has a special hook involving that cleric level you just gained. As a player, ask the DM if he has special plans to make that cleric level more purposeful, or if it is, "just up to you."
As a DM, I would see it as an opportunity to grant the use of a unique magic item, perhaps even an artifact. The fact that you have visited with Kord's avatar as part of your "new life" might include the granting of a unique ability more appropriate for your level (e.g., automatically highten all spells cast to 5th-level caster, or invoking the name of Kord during battle grants you rage abilities).
If I were the DM, here are some thoughts on what I might do:
1. You gain the outsider type to represent your second life, and a susceptability to certain magic that can sever that life more easily. You won't be coming back in a third life should you lose this one.
2. Your (unique and divinely gifted) holy symbol allows you (and other outsiders of Kord), to heighten spells at +4 caster levels with no casting cost. In addition, it grants +4 caster levels when used to turn undead, and allows Divine Might 1x/day.
3. When invoking the name of Kord, you can spontaneously call forth one 3rd or lower level cleric spell once per day. This spell does not count against your prepared spells per day. This can be used in place of the Divine Might ability. This is a supernatural ability which requires this specific holy symbol, which was created by an avatar of Kord.
There's room to make this a more interesting change than just granting a single cleric level, but it really is up to the DM to make it more meaningful mechanics-wise.
Being one level behind the rest of the party isn't such a bad penalty for being reborn IMO, regardless of being stuck with one level of another class or not. But, I think even your DM would want you to get more mileage out of your cleric level.
If your DM meant to penalize you for your death, than I would probably skip the divine might/spontaneous casting ability, or maybe more, but my impression is that you earned something, and as a result of communing with Kord, found that you would prove useful to him if granted a second life. I think the gifted abilities above would help to compensate for the low cleric level enough to make it useful, while not overshadowing the other characters. Together with my suggestions, I think it makes it worthwhile to pursue more cleric levels, which is how I would want to present it if it were my campaign, and I think Kord would want it that way too.
