Confusion related to Jhanas' involvement on the path

I have a two-part question. One is related to personal practice and the other is scriptural or theoretical. I'll lay down a concise personal background for the sake of clarity. I am an irregular practitioner of Vipassana. I have finished 3 Vipassana retreats (Goenka tradition). I try to meditate for 2 hours a day most days. I also attempt walking and sleeping meditation as much as I can at times when I'm not formally meditating. **Question 1** It had been difficult for me to establish equanimity in body scanning since i was getting distracted too often. So I allowed myself to indulge in just doing anapana sati (samatha meditation). While I thought I was just doing anapana sati, I probably unconsciously was doing insight meditation too by using the nostrils as the object (I'm not sure if that's what it is, please correct me if I'm wrong). I would try to attain equanimity towards the sensations within my nostrils. My breath would increase pace when i would fail to get the sensation. I would then try to slow it down to natural pace which is super subtle, by attempting to be equanimous about the CURRENT sensations and eliminating all cravings. When i would succeed, the breathing would become too subtle, too short, too sharp and too fast to notice and yet I'd be effortlessly noticing it without affecting the pace of the breath. At this point I would experience the below mentioned state. I'm not sure if this state is the first jhana or not but it's the most significant experience I've had as of yet while formally meditating. It has following characteristics: 1. a feeling that breathing (the area of nostrils) is the handle through which the instrument of my whole body is being held with 2. a uniform sense of numbness throughout the body 3. a steady awareness of the non-uniform subtle sensations on the body yet simultaneously uniform and unbroken sense of equanimity towards all of the sensations 4. the feeling of "MY body" being retracted/sinking within the objective body as if the ME is far away from the surface of the body 5. a mild pleasure arising from the realization of the momentary freedom from surface sensations Note: I've experienced this state multiple times but usually when it occurs, i get taken by surprise and either get too excited about it or anxious about the possibility of it ending, in both cases it actually does end up terminating the state. **Q: Is this any of the rupa jhanas or am I just experiencing normal precursor stages before entering the first jhana?** **Question 2** I've been obsessively delving into Buddhist literature through various PDFs, forums such as this and meditation related subreddits as of late. I haven't formally studied the canon. So please forgive my ignorance. I read somewhere (I don't recall where) that if one progresses through the arupa Jhanas (Samadhi) without making any progress in the insight (Panna) then after death, the citta is reborn in the formless realm (arupa loka) and has to stay there for a long, long time until the pleasant sankharas run out after which one returns to the material realm whence one can continue the journey towards liberation through insight practice.   **Q: is it true that too much progress in Samadhi and little progress in Panna can lead to rebirth in arupa/deva/brahma loka which would actually delay the progress towards liberation? if it's true, then how farther would it be safe to progress in jhanas to secure rebirth in human realm so that one can keep working towards nibbana?**   Thank you for your patience! Much metta!