Well, I'm not professional at this, but here's my advice.

I think you need to get back on the bike more, but at a reduced intensity. A very reduced intensity. For me, I'm starting to really hurt at about 160 BPM, and my max is around 171 BPM. If I'm doing active recovery, I don't go above 110 BPM.

I'd suggest 3 days a week for an hour or so each, and back of from the weight training. Look at what you're eating - less refined stuff, more fresh food.

You could also have a bit of virus. It's not uncommon to get something where you get a little run down but don't feel really sick.