@helpasap,
Hi helpasap, I'm sure you know that talk's response is a major generalization but since you selected that response... in my situation, we got married when I was 25 and he was 27, and had been together for four years at that point (we've now been together for 18 years).
The period before the wedding is definitely stressful, especially if you're doing all the work yourself. I've noted before that I think things might have evolved that way for a reason -- that if you can get through the pre-wedding stress, your marriage has a good chance (and if you can't, you don't get married in the first place).
Not kissing each other anymore doesn't sound good. I think I'd start there. Talk to him about that and your concerns, see where things go.
I get what GreenWitch means about the party but if you have serious concerns a) the party won't be as fun, b) the ceremony + party won't be as meaningful, and c) the guests might get pissed off if they're going to any trouble to attend, give you gifts, etc. and then next week you're like yeah, we're not sticking together after all.
You have some time, not a ton but some. I think you guys should use that to figure some things out before the party.
Good luck!