Unfortunately the shaking and headaches are pretty common on clen, but you probably already know this since your familiar with using tabs. Now I haven't personally done an injectable form of clen but I have taken liquid clen and the headaches were pretty normal when starting out a cycle again. As mentioned, I think the key is really to start low and work up. When I use to start too high the headaches and side effects would be much more pronounced.

There's not much you can do about the shaking, but cramping can be fixed with adding in some taurine/potassium. As far as headaches you can't really prevent them, but carrying around some extra strength tylenol at all times helped me get through the really bad days.

One of the reasons I haven't gone back to clen is just that the benefits from it didn't outweigh the side effects for me personally.