It sounds like you're having difficulty finding a way to experience pleasure from both partnered and solo sex, which can be really frustrating. This is a really common experience for many people, so first please be assured that your body is normal and you are not at all alone in this.
When you say that you don't find the idea of sex "appealing", you have thoughts about it being "dirty" and it can make you feel a bit "grossed out" and uncomfortable. Would you feel comfortable unpacking this a bit more by describing how or why these thoughts occur to you?
A lot of the scripts we are given by society and the media tell us that sexual pleasure comes directly from physical stimulation, however this is not the case. Instead, our brain is a really important part of the process of sexual response: it plays a big part in desire and arousal, which are important parts of a process called the Sexual Response Cycle. Simplified, what this means is that without experiencing desire and arousal, physical stimulation is not going to create pleasurable feelings on its own. You can read more about this here: Sexual Response & Orgasm: A Users Guide
Hopefully the above is a useful in assuring you that your body is responding in a way that is expected when a body isn't aroused.
With regards to feeling arousal, your answers to the above questions regarding your personal thoughts will shed more light on this. For some, lack of arousal can be an indicator that they are indeed on the asexuality spectrum, and for others, it can be because of other thoughts and feelings about sex causing stress and impeding arousal. It can also be that exploring physical pleasure in this way isn't what's right for you right now. I'll expand on these ideas below with some resources, potentially there will be some that resonate with you more than others.
The asexuality spectrum is diverse, and you will always be the best expert on what identity best resonates with you. Below are some articles that you might find useful, do any of the descriptions resonate with you? It is also completely fine if your answer to the below is "IDK" or "not sure".
It is important also to remember that sexual folks don't experience automatic desire or arousal. Arousal can be hard if our brain is preoccupied with thoughts of insecurities about our bodies, cultural scripts about sex being "shameful" or taboo, putting pressure on ourselves, or we are dealing with stress in other parts of our lives that is putting the breaks on our sexual response cycle. Below are some advice columns that unpack this a bit more, do these resonate with you at all? Moreso or less than the Asexuality resources listed before? (again "idk" is a fine answer here).
There is a lot of information here, so it is important to add there is no requirement for you to "know" all the answers right now
. Exploring our sexuality and understanding ourselves is a process that will continue throughout our lives, and we are all on our own timeline. What this means is that it is also fine to take a break from sexual self exploration, rather than putting pressure on ourselves to work out what we like so we don't "miss out". Taking the pressure off yourself might look like taking some time off this exploration a few days or however long you need, and doing things you enjoy instead. Does that make sense?