Please come to graduate school — we need students like you.
It's great that you are interested in all the things; you are not alone. There are other graduate students and academics who are interested in all the things, and it is a healthy sign of someone who has a broad interest in their field. Now, you can't really write a dissertation on "all the things", so at some point in your graduate work you are going to have to narrow things down to a topic that is sufficiently demarcated that you can do some novel and substantial research on it. You are going to have to specialise and go deep in your research on a particular topic. But since you are interested in all the things, it shouldn't be too difficult to find one thing that is interesting enough for a program of research.
Depending on the particular university, in a PhD program in graduate school you may or may not be expected to specialise "right out of the gate". At most universities you would do a year where you are either doing broad graduate-level coursework, or reading broadly over your field. In this period you are expected to be on the lookout for topics for a dissertation, but you are not expected to specialise right away. However, as you progress through the program you will be expected to choose a topic, begin to specialise in this topic, and study deeply into this topic in order to make a substantive research contribution in it. There are some universities where you will be expected to give a PhD proposal at entry and in this case there may be an expectation of earlier specialisation. If you're unsure, talk to the graduate coordinator at the university you are interested in and find out the process they use.
As to whether you can simultaneously study other fields, yes you can, but your time for this will be limited. Doing research in a field takes quite a lot of discipline and effort (particularly when you are first learning it) and so you may find that your spare time for studying other fields gets squeezed down a bit. Ideally you can progress your PhD research in a specialised field while also having some time available to learn about other things. (In fact, the latter can be a good way to take a break when you need it; do specialised study in some subfield of English, and then take a break by reading a philosophy book you're interested in.) Note that even once you have chosen a topic for your dissertation, you will specialise in this topic during your PhD candidature, but you can move into other topics later. If you've read widely this will help you to get research ideas on all sorts of topics in your later career. There are many academics and other researchers who have done a PhD dissertation in one topic/field, but then moved away from that or branched out in their later research.
There is absolutely room for you people like you in graduate school. In fact, I would say that it would be lovely to have more students like you. Please try your best not to lose that broad interest and love for multiple fields of inquiry, even if you spend years forced to specialise in particular topics. I'm a fellow "jack-of-all-trades", and I'll be honest that it does make it harder to advance in academia. (Academia primarily rewards high levels of output in a specialised subfield.) But it's certainly not impossible, and it's sometimes nice to be that guy with very broad knowledge across multiple fields.
As a caveat on the above, I suppose I shouldn't be too gung-ho on you coming to graduate school, since I don't want to ruin your life. Graduate school can be difficult for many students, and a graduate degree in English/Philosophy is arguably a terrible career move compared to entering the workforce. Moreover, there is a fairly substantial overproduction of graduate research students at the moment, which bodes poorly for future job prospects and social stability (see e.g., here and here). Nevertheless, if you love your subjects enough, and are prepared to make less money and have worse job-security than your peers, then by all means come on in.