First of all, I applaud you for not giving in to fear. As a mom one of the most important things you can do is stay level headed and not blow things out of proportion. Good job.
In answer to your 2nd question, Yes, it is perfectly normal to bleed that long and it can overlap your period especially if you aren't nursing.
I remember when my second daughter was born. I took her to the doctor and commented on what a little chub she was. The doctor just looked at me and said " I wish all I had to do was look at fat, healthy babies all day long." His point was well taken. If you have a baby who is gaining weight and thriving, that is such a blessing.
A 5 1/2 week old baby should be eating about 24 ounces in a 24 hour period. I would try to feed him about 4 ounces at a time and then stop and observe him. Don't confuse his desire to suck or even his fussiness for a lack of satisfaction or not being full. There are clues to look for to determine when a baby is full. Their little hands relax out of the tight fist, their tummy is round and tight. They start to look around or settle down.
If he is always fussy I would start by trying 3 things.
1. Make sure to give full feedings not just snack feedings. It's tempting to offer the bottle every time a baby fusses but when it's time to eat, he should be hungry and focused and take the full bottle, not just drink 2 ounces, wait an hour, 2 more ounces. I'm in no way insinuating you don't feed a hungry baby. Just telling you after having three babies of my own that snacking instead of eating, prevents the baby from getting good naps and when a baby is not sleeping enough, they stay fussy.
2. Frequently burp him during feedings and use a bottle that removes gas. Playtex Nursers with the plastic inserts are my favorite. If he is throwing up a lot it's a good chance you are over feeding him. If he throws up all the time no matter how much he eats, you may want to try a different formula. Our first daughter had horrible stomach issues and we went through about 4 different formulas before we found one that didn't upset her stomach. We've used a different formula for each of our babies because they are just all different. But the Playtex nursers work great to help with gas.
3. The last thing, and this relates to wanting to suck, is to offer a pacifier after 4 ounces. Some babies won't take a pacifier - my first two didn't, but if he will, just offer it to him and then observe. Is he sucking fast and furiously and stopping frequently to cry? He may still be hungry. Is he sucking contentedly and looking more relaxed and full? He probably just wants to suck.
I want to mention one more thing which may or may not apply to you and may not be a popular view. I've learned not to wake my babies up to eat. I know people tell you to wake them up and if he was failing to thrive I would agree but he is gaining plenty of weight. I've found with my babies that if I will just let them sleep as long as they want, they will wake up hungry and ready to take a full feeding. They also are much more cheerful and content over all because their body knows how much sleep they need and waking them up disrupts that sleep pattern. Again - not if they are losing weight, but if they are healthy and fine and sleeping - let them be.
I hope that helps. Praying peace over you and your little one.
A.