I’m feeling regretful

I don't know if this is a good idea. But I understand the pressure of calling something off two days before. Relationships are not always 50/50. My fiance currently works two jobs while I work part time. I have some health issues and I'm trying to dedicate time to starting a business as well. I'm currently miserable at ,y job and he's trying to get me to quit because he knows the job has been rough on me and wants me to give all of my time to my business. He even said he'd get a third job ( I obviously turned that down ) if we needed it so I could have the time. To me, that's what being a partner is. Having communication when one of you is struggling and sometimes taking on extra weight, whatever that looks like in your relationship, for the other person.

You sound like you're having communication issues that you guys need to work through. I would trust your gut

Your head is trying to tell you something. Listen. I agree wholeheartedly with Alyssa. Some age gaps are normal, and I'm not judging you but people 15 years apart have are usually in completely different life stages, have different maturity levels, and differ greatly in emotional maturity.

The fact that HE, the OLDER of you two, is the one lacking in emotional maturity, is a huge red flag. If he was up to the task of being a great husband, he would already be with someone his age. Hold off on your marriage and decide if you want to be with someone who is unable to communicate because "leave me alone for the whole day" and guilting you about what he does for you is 100% not normal!

I completely agree with everyone saying to trust your gut, and sadly if that means you have to call off the wedding then you have to do what is best and right not only for you but also your daughter.
If you are giving your absolute all, mentally, emotionally and financially and he isn't reciprocating that back to you in the same ways, but instead sounding off and lashing out on you by telling you to leave him alone for the rest of the day, then there is something certainly not right. It's like what Alyssa said, there is a reason as to why he cannot find or be with people/someone around his own age, believe me! My ex-husband is 7 years older than I am and the difference in maturity level is astounding, then and now, as he has not changed any of his ways and now his new and 10 years younger wife is learning about it. In which it has also gotten to the point where our nearly 10 year old son has started recognizing it and expressing his dislike of his Dad's behavior to me.

I will admit that I went through these feelings as well before I married my ex-husband, even having a full on panic attack the moment before I was supposed to walk down the aisle. It is a very difficult topic to think about and make a decision on. So take a few moments to yourself, make a pros vs cons list if you need to and think it will help, because what you think and how you feel in this situation truly matters, as well as how it could affect your daughter.

You guys need to have a discussion and get on the same page ASAP if you're going to get married.

Him needing to cool off when he's upset or him feeling unappreciated aren't necessarily death knells, but they ARE things that need to be communicated. Sometimes when my FH and I are arguing, we agree we both need to cool off and collect our thoughts before we can have a productive conversation, but it's ALWAYS followed up by a productive conversation. The understanding is that we're going to solve the issue, not ignore the other person's feelings when they say something hurt them. Just storming off and not addressing something isn't going to solve anything.

Likewise, while your fiancé may feel unappreciated by others from time to time, he needs to recognize how making blanket statements like that impact you. Saying nobody does anything for him like he does for them is both selfish and hurtful when you're doing A LOT for him. Does he appreciate YOU for the things that you do? How would he feel if he tried to tell someone they hurt him, but they stormed off and made the problem about them?

I get that he may be feeling extra emotional/ worn out due to it being the anniversary of his mothers' passing, but that doesn't give him a free pass to hurt others or be dismissive of their feelings. If this is a habitual thing for him, I'd take a hard look at whether this is something you want to put up with for life.