normally I have regular periods except recently they haven't been

I'm 23, normally have regular periods except recently they haven't been. My last regular(what's regular and normal for me) was March 27-31. My cycles are usually 25-28 days averaging 28. I've had very few 29 and 30 day. Normally periods are 3-5 days and more likey 4 days. Flow is usually medium,sometimes heavy w/ clots. 

However my last 2 cycles were 39 and 34 days. The 39 was 13 days late and 34 7 days. 39 was in May. 34 in June. No period in April. It was 4 days in June. Only 1 day(and barely,I would say only a 12hr one if that). I know this sounds gross but I don't know how else to describe it but I only knew I started because I felt like I leaked out. When I felt this both in May and June it was red blood,but very little. After this intial red blood, it has stayed light brown. It's also been really light, not even enough to fill up a tampon and I was using regular as it's all I had. 

I was going to take a hpt but I had this weird "period" and figured there was no point in May. In June when it was late again I was going to do the same. 

Now it's July and I was suppose to start the 5th. 

First off I'm not on birth control, nor am I stress(I was in January but that was it but stress in high school never delayed my periods and I was stressed more in high school at times than in January). I'm a healthy weight and it hasn't changed recently. Actually I stay at the same weight pretty much all the time,maybe a little flucuation but not much like 1-2 lbs. I have not been sick recently. As far as I know I do not have pcos & looking up symptoms don't think I do either. I really don't think I have cysts or fibroids  based off symptoms online. Any top causes for delayed periods just doesn't fit me.

I seen my primary doctor in June and told him but he said he couldn't think of why knowing my health history and that I wasn't stressed and said it was better I see my obgyn. Well I am seeing her but couldnt get in until the end of this month. 

I haven't been feeling nausea really unless I get a migraine(I get them anyways). I have noticed an increase in the past couple months of migraines/headaches. Also feeling dizzy & light-headed and well my primary gave me medicine for vertigo but didn't come out and say I have vertigo but I fit the symtpoms. I'll be dizzy just laying in bed. I have noticed an increase in urination but I also have been drinking more water so I don't know if that has to do with it.

I did have mild cramping in May and more than usual but not severe. It started about 2 weeks before my expected period and lasted on and off until my "period" came. I don't remember if I did in May but if I did it was more mild and less. This month not really much at all but more a "heavy" or "bloated" feeling. Increase in heartburn & acid reflux especially during sex and I never have had it happen during sex. I wouldn't really say I have food aversions but sometimes I can be hungry and just not feel like eating what's in the fridge, like nothing looks good. I did once make mac & cheese & it smelled a little fowl & made me nauseous but eating it was fine. Been dealing with constipation as well. Increased discharge but it doesn't smell, itch or burn. No does it look clumpy, more creamy white. Also had mild lower back pain.

Another thing is I usually can suck in my entire abdomenal area but recently cannot suck in the are below my belly button and sometimes when I suck in and usually I noticed I have to pee so maybe my bladder is full, I noticed a "bulge" or ball-like lump below my belly button. But after I pee it goes down some. 

While waiting for my appointment I've been trying to figure out myself what it might be and well it's crossing my mind more it may be pregnancy since I do know some can have slight bleeding especially during their first trimester. 

Just tell me what you think. I will say I did in fact have sex in April during my ovulation week(according to the app I was ovulating and I noticed stretchy-clear discharge) I also had sex in May & June. I will say we do use the pull-out method when he does ejaculate as he doesn't all the time. I know this isn't effective as I'm 23 but I know the consquences and well my partner & I can afford a child so that's not an issue just wasn't really trying for one right now but both agreed if it happens, it happens. I know pre-cum can have sperm in it too which is why the method isn't always effective. 

Sorry it's long but I feel I shouldn't leave anything out. Like I said, I have an appointment and I'm sure she will test me but I would just like others opinions to be prepared for if it might be pregnancy.