The below response may or may not be helpful depending on the copyright laws of your university/country etc (this is based on Australia):
I just completed my PhD so I can enlighten you a bit, having published papers during the course of my PhD that was then used in the body of my thesis.
I published an article based on a chapter I had written, and then reincorporated that article back into my chapter (effectively 'updating' the chapter).
I didn't have to worry about any copyright issues regarding tables/figures/material nor did I have to cite the information.I was able to really just copy and paste it in. All I had to do was write in my acknowledgements:
Parts of ___ have been previously published as (insert citation here).
I was able to do this, because I chose to NOT publish my thesis as an ebook through the university (nor did I choose to publish it as a book). Your thesis is not considered a publication unless it is published as an academic book, or as an ebook (online copies through the library are not considered ebooks). This also meant that any pictures (of which I had plenty) only required citation information/source information, but I did not have to seek permission to use those images. If I wanted to publish the images in a paper or book, I would have to seek permission.
If you are planning to publish your thesis as an ebook or academic book, that is when you will run into self-plagiarism issues.
My advice? Do not opt to publish your thesis as an ebook/academic book. You've already published three papers (which is fantastic!) from your data, continue to go that route.
This means you can use as much as you want from your publications into your thesis.
Of course, this is the practice where I studied, as others have suggested, get in touch with your supervisor about these issues as well as the copyright experts (usually associated with the library).
Generally though, you don't have to worry about copyright regarding reincorporating your journal articles back into your thesis UNLESS you then decide to publish said thesis. You don't even need to cite the information you've used from your journal articles if they were formed from the data of your doctorate.
This is of course, based on the idea that your journal articles were based on your thesis chapters and are not too different/not relevant to your thesis.