I think my [15M] social anxiety will ruin my relationship

As the title says I have social anxiety and it's affecting me massively.I've been with my GF [15F] for 2 and a half months now, she knows I have social anxiety and realistically everything is going perfectly, however, my anxiety is destroying me and convincing me she hates me. I've had more anxiety attacks in the last 2 months then I had in the year prior.One of the main issues is that we are both pretty abysmal at texting and one of my triggers is people not replying to text messages. My logic can tell me that realistically she is just busy but my social anxiety will not stop abusing my brain until she responds or I get confirmation that she is busy. My social anxiety will constantly try to persuade me that she is ignoring my messages and doesn't want to talk to me, but that is always provided wrong because she will always apologies allot afterwards.Another issue I face is the fact that I really struggle to compliment and tell her how I feel. I have slowly been getting better at this but still struggle to compliment her because of my fear of being judged, even if I do compliment her it takes a lot of confidence. I find it easier to say how I feel and compliment her over text but due to my first issue, it can also make it even worse.There's a multitude of different issues but the last one I will list is also the most confusing. I can spend a whole day with her and it can go perfectly and she can message me saying she loved it but my social anxiety will convince me that she hated it. For example, yesterday I spent the whole day with her and we spent most of the time cuddling with her initiating allot of kissing. Afterwards, we messaged saying how much we enjoyed it but the first issue happened and over time my social anxiety ate away at my brain until I was convinced she hated it and will never want to meet up with me again.I know that I should get help and I know how I can get it but I have a constant fear that whoever I end up seeing will judge me and I can't bring myself to telling my mum that my anxiety has gotten worse.In conclusion, does anyone know how I could help my anxiety or have any tips to deal with my first issue?