Poacher - just back off everything and look after yourself. You sound really beaten up. Then reassess and see what you fancy doing?
It's a puppy not a cat. He is lovely but keeping me busy.
SEdan - the only limits are the ones you set yourself. Why not see where your training takes you and then decide what your goals are? Berlin is a nice fast course. I managed 3:07 on 7 weeks' training and a very easy 2nd half. I reckon it would have been a few minutes slower at London with that approach.
Any Surrey locals want to join me in the Hogs Back Race this Sunday? I have had to shelve plans to run the Dorset trail race as MrE is at Twickenham so have signed up for the Hogs Back instead.
And remember, CV fitness comes on much more quickly than soft tissue resilience so you are smart to think about tendon strength. With consistency that will come in time but much later than the aerobic fitness so you will have to be super patient. You can improve tendon strength with loading at home, simple eccentric calf loading exercises can be really helpful, for example, or just slowly going up on raised toes and lowering down to work those tibia tendons and strengthen the toes. Lots of stuff on youtube to given you an idea how to approach it.